@article {1490021, title = {Dilute Alloys based on Au, Ag, or Cu for Efficient Catalysis: from synthesis to active sites }, journal = {Chemical Reviews }, volume = {122}, year = {2022}, url = {https://pubs.acs.org/doi/10.1021/acs.chemrev.1c00967}, author = {Jennifer D. Lee and Jeff B. Miller and Anna V. Shneidman and L. Sun and J. F. Weaver and Joanna Aizenberg and J. Biener and J. A. Boscoboinik and Amanda C. Foucher and Anatoly I. Frenkel and Jessi E. S. van der Hoeven and Boris Kozinsky and Nicholas Marcella and Matthew M. Montemore and Hio Tong Ngan and Christopher R. O{\textquoteright}Connor and Cameron J. Owen and Eric A. Stach and Robert J. Madix and Philippe Sautet and Cynthia M. Friend} } @article {1436721, title = {Self-regulated non-reciprocal motions in single-material microstructures}, journal = {Nature}, volume = {605}, year = {2022}, pages = {76-83}, abstract = {

Living cilia stir, sweep and steer via swirling strokes of complex bending and twisting, paired with distinct reverse arcs. Efforts to mimic such dynamics synthetically rely on multimaterial designs but face limits to programming arbitrary motions or diverse behaviours in one structure. Here we show how diverse, complex, non-reciprocal, stroke-like trajectories emerge in a single-material system through self-regulation. When a micropost composed of photoresponsive liquid crystal elastomer with mesogens aligned oblique to the structure axis is exposed to a static light source, dynamic dances evolve as light initiates a travelling order-to-disorder transition front, transiently turning the structure into a complex evolving bimorph that twists and bends via multilevel opto-chemo-mechanical feedback. As captured by our theoretical model, the travelling front continuously reorients the molecular, geometric and illumination axes relative to each other, yielding pathways composed from series of twisting, bending, photophobic and phototropic motions. Guided by the model, here\ we choreograph a wide range of trajectories by tailoring parameters, including illumination angle, light intensity, molecular anisotropy, microstructure geometry, temperature and irradiation intervals and duration. We further show how this opto-chemo-mechanical self-regulation serves as a foundation for creating self-organizing deformation patterns in closely spaced microstructure arrays via light-mediated interpost communication, as well as complex motions of jointed microstructures, with broad implications for autonomous multimodal actuators in areas such as soft robotics, biomedical devices\ and energy transduction materials, and for fundamental understanding of self-regulated systems.

}, author = {S Li and Lerch, MM and Waters, James T. and Deng, B. and Martens, Reese S and Yao, Y. and Kim, D. and Bertoldi, K. and Grinthal, A. and Balazes, A and Aizenberg, Joanna} } @article {1429362, title = {Decoding reactive structures in dilute alloy catalysts}, journal = {Nature Communications}, volume = {13}, year = {2022}, pages = {1-9}, abstract = {

Rational catalyst design is crucial toward achieving more energy-efficient and sustainable catalytic processes. Understanding and modeling catalytic reaction pathways and kinetics require atomic level knowledge of the active sites. These structures often change dynamically during reactions and are difficult to decipher. A prototypical example is the hydrogen-deuterium exchange reaction catalyzed by dilute Pd-in-Au alloy nanoparticles. From a combination of catalytic activity measurements, machine learning-enabled spectroscopic analysis, and first-principles based kinetic modeling, we demonstrate that the active species are surface Pd ensembles containing only a few (from 1 to 3) Pd atoms. These species simultaneously explain the observed X-ray spectra and equate the experimental and theoretical values of the apparent activation energy. Remarkably, we find that the catalytic activity can be tuned on demand by controlling the size of the Pd ensembles through catalyst pretreatment. Our data-driven multimodal approach enables decoding of reactive structures in complex and dynamic alloy catalysts.

}, url = {https://www.nature.com/articles/s41467-022-28366-w}, author = {Marcella, N and Lim, J S and Plonka, A M and Yan, G and Owen CJ and van der Hoeven, JES and Foucher, AC and Ngan, HT and Torrisi, SB and Marinkovic, NS and Stach, E.A. and Weaver, JF and Aizenberg, J and Sautet, P and Kozinsky, B and Frenkel, A} } @article {1429357, title = {Mapping blood biochemistry by Raman spectroscopy at the cellular level }, journal = {Chemical science}, volume = {13}, year = {2022}, pages = {133-140}, abstract = {

We report how Raman difference imaging provides insight on cellular biochemistry\ in vivo\ as a function of sub-cellular dimensions and the cellular environment. We show that this approach offers a sensitive diagnostic to address blood biochemistry at the cellular level. We examine Raman microscopic images of the distribution of the different hemoglobins in both healthy (discocyte) and unhealthy (echinocyte) blood cells and interpret these images using pre-calculated, accurate pre-resonant Raman tensors for scattering intensities specific to hemoglobins. These tensors are developed from theoretical calculations of models of the oxy, deoxy and met forms of heme benchmarked against the experimental visible spectra of the corresponding hemoglobins. The calculations also enable assignments of the electronic transitions responsible for the colour of blood: these are mainly ligand to metal charge transfer transitions.

}, url = {https://pubs.rsc.org/en/content/articlelanding/2022/SC/D1SC05764B}, author = {Volkov, V and McMaster, J and Aizenberg, J and Perry, Carole} } @article {1429352, title = {Patterned crystal growth and heat wave generation in hydrogels}, journal = {Nature Communications}, volume = {13}, year = {2022}, pages = {1-11}, abstract = {

The crystallization of metastable liquid phase change materials releases stored energy as latent heat upon nucleation and may therefore provide a triggerable means of activating downstream processes that respond to changes in temperature. In this work, we describe a strategy for controlling the fast, exothermic crystallization of sodium acetate from a metastable aqueous solution into trihydrate crystals within a polyacrylamide hydrogel whose polymerization state has been patterned using photomasks. A comprehensive experimental study of crystal shapes, crystal growth front velocities and evolving thermal profiles showed that rapid growth of long needle-like crystals through unpolymerized solutions produced peak temperatures of up to 45oC, while slower-crystallizing polymerized solutions produced polycrystalline composites and peaked at 30oC due to lower rates of heat release relative to dissipation in these regions. This temperature difference in the propagating heat waves, which we describe using a proposed analytical model, enables the use of this strategy to selectively activate thermoresponsive processes in predefined areas.

}, url = {https://www.nature.com/articles/s41467-021-27505-z}, author = {Schroeder, TBH and Aizenberg, J} } @article {1429356, title = {Highly Ordered Inverse Opal Structures Synthesized from Shape-Controlled Nanocrystal Building Blocks}, journal = {Angewandte Chemie International Edition}, volume = {61}, year = {2021}, abstract = {

Three-dimensional ordered porous materials known as inverse opal films (IOFs) were synthesized using nanocrystals with precisely defined morphologies. Comprehensive theoretical and experimental studies of the volume fraction ratio and electrostatic interactions between nanocrystals and polystyrene templating particles enabled the formation of highly ordered crack-free photonic structures. The synthetic strategy was first demonstrated using titanium dioxide (TiO2) nanocrystals of different shapes and then generalized to assemble nanocrystals of other functional materials, such as indium tin oxide and zinc-doped ferrite. Tunable photocatalytic activity of the TiO2\ IOFs, modulated through the choice of the shape of TiO2\ nanocrystals in conjunction with selecting desired macroscopic features of the IOF, was further explored. In particular, enhanced activity is observed for crack-free, highly ordered IOFs whose photonic properties can improve light absorption via the slow light effect. This study opens new opportunities in designing multi-length-scale porous nanoarchitectures having enhanced performance in a variety of applications.

}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202111048}, author = {Han, J.H. and Shneidman, A.V. and Kim, DY and Nicolas, NJ and van der Hoeven, J and Aizenberg, M. and Aizenberg, J} } @article {1429351, title = {Spiropyran Photoisomerization Dynamics in Multiresponsive Hydrogels}, journal = {Journal of the American Chemical Society}, volume = {144}, year = {2021}, pages = {219}, abstract = {

Light-responsive, spiropyran-functionalized hydrogels have been used to create reversibly photoactuated structures for applications ranging from microfluidics to nonlinear optics. Tailoring a spiropyran-functionalized hydrogel system for a particular application requires an understanding of how co-monomer composition affects the switching dynamics of the spiropyran chromophore. Such gels are frequently designed to be responsive to different stimuli such as light, temperature, and pH. The coupling of these influences can significantly alter spiropyran behavior in ways not currently well understood. To better understand the influence of responsive co-monomers on the spiropyran isomerization dynamics, we use UV{\textendash}vis spectroscopy and time-dependent fluorescence intensity measurements to study spiropyran-modified hydrogels polymerized from four common hydrogel precursors of different pH and temperature responsivity: acrylamide, acrylic acid,\ N-isopropylacrylamide, and 2-(dimethylamino)ethyl methacrylate. In acidic and neutral gels, we observe unusual nonmonotonic, triexponential fluorescence dynamics under 405 nm irradiation that cannot be explicated by either the established spiropyran{\textendash}merocyanine interconversion model or hydrolysis. To explain these results, we introduce an analytical model of spiropyran interconversions that includes H-aggregated merocyanine and its light-triggered disaggregation under 405 nm irradiation. This model provides an excellent fit to the observed fluorescence dynamics and elucidates exactly how creating an acidic internal gel environment promotes the fast and complete conversion of the hydrophilic merocyanine speciesto the hydrophobic spiropyran form, which is desired in most light-sensitive hydrogel actuators. This can be achieved by incorporating acrylic acid monomers and by minimizing the aggregate concentration. Beyond spiropyran-functionalized gel actuators, these conclusions are particularly critical for nonlinear optical computing applications.

}, url = {https://pubs.acs.org/doi/abs/10.1021/jacs.1c08778}, author = {Meeks, A and Lerch, MM and Schroeder, TBH and Shastri, A. and Aizenberg, J} } @article {1429349, title = {Bioinspired design and optimization for thin film wearable and building cooling systems}, journal = {Bioinspiration \& biomimetics}, volume = {17}, year = {2021}, pages = {015003}, abstract = {

In this work, we report a paradigmatic shift in bioinspired microchannel heat exchanger design\ toward its integration into thin film wearable devices, thermally active surfaces in buildings, photovoltaic devices, and other thermoregulating devices whose typical cooling fluxes are below 1 kW m-2. The transparent thermoregulation device is fabricated by bonding a thin corrugated elastomeric film to the surface of a substrate to form a microchannel water-circuit with bioinspired unit cell geometry. Inspired by the dynamic scaling of flow systems in nature, we introduce empirically derived sizing rules and a novel numerical optimization method to maximize the thermoregulation performance of the microchannel network by enhancing the uniformity of flow distribution. The optimized network design\ results in a 25\% to 37\% increase in the heat flux compared to non-optimized designs. The study demonstrates the versatility of the presented design\ and architecture by fabricating and testing a scaled-up numerically optimized heat exchanger device\ for building-scale and wearable applications.

}, url = {https://iopscience.iop.org/article/10.1088/1748-3190/ac2f55/meta}, author = {Grinham, J and Hancock, MJ and Kumar, K and Bechthold, M and Ingber, DE and Aizenberg, J} } @article {1429346, title = {Finite-difference Time-domain (FDTD) Optical Simulations: A Primer for the Life Sciences and Bio-Inspired Engineering}, journal = {Micron}, volume = {151}, year = {2021}, pages = {103160}, abstract = {

Light influences most ecosystems on earth, from sun-dappled forests to bioluminescent creatures in the ocean deep. Biologists have long studied nano- and micro-scale organismal adaptations to manipulate light using ever-more sophisticated microscopy, spectroscopy, and other analytical equipment. In combination with experimental tools, simulations of light interacting with objects can help researchers determine the impact of observed structures and explore how variations affect optical function. In particular, the finite-difference time-domain (FDTD) method is widely used throughout the nanophotonics community to efficiently simulate light interacting with a variety of materials and optical devices. More recently, FDTD has been used to characterize optical adaptations in nature, such as camouflage in fish and other organisms, colors in sexually-selected birds and spiders, and photosynthetic efficiency in plants. FDTD is also common in bioengineering, as the design of biologically-inspired engineered structures can be guided and optimized through FDTD simulations. Parameter sweeps are a particularly useful application of FDTD, which allows researchers to explore a range of variables and modifications in natural and synthetic systems (e.g., to investigate the optical effects of changing the sizes, shape, or refractive indices of a structure). Here, we review the use of FDTD simulations in biology and present a brief methods primer tailored for life scientists, with a focus on the commercially available software\ Lumerical FDTD. We give special attention to whether FDTD is the right tool to use, how experimental techniques are used to acquire and import the structures of interest, and how their optical properties such as refractive index and absorption are obtained. This primer is intended to help researchers understand FDTD, implement the method to model optical effects, and learn about the benefits and limitations of this tool. Altogether, FDTD is well-suited to (i) characterize optical adaptations and (ii) provide mechanistic explanations; by doing so, it helps (iii) make conclusions about evolutionary theory and (iv) inspire new technologies based on natural structures.

}, url = {https://reader.elsevier.com/reader/sd/pii/S0968432821001517?token=C3A313DCB1A3C9779A241A4F9B4C2A818CC936DA87D0281483E35F4645C65E29B4D1D0D79CCBEEF775592793CBBB7781\&originRegion=us-east-1\&originCreation=20220215203155}, author = {McCoy DE and Shneidman AV and Davis, AL and Aizenberg, J.} } @article {1415768, title = {On the Origin of Sinter-Resistance and Catalyst Accessibility in Raspberry-Colloid-Templated Catalyst Design}, journal = {Advanced Functional Materials}, year = {2021}, pages = {2106876}, abstract = {

Nanoparticle (NP) sintering is a major cause of the deactivation of supported catalysts. Raspberry-Colloid-Templated (RCT) catalysts are an emerging class of materials that show an unprecedented level of sinter-resistance and exhibit high catalytic activity. Here a comprehensive study of the origin of NP stability and accessibility in RCT catalysts using theoretical modeling, 3D electron microscopy, and epitaxial overgrowth is reported. The approach is showcased for silica-based RCT catalysts containing dilute Pd-in-Au NPs previously used in hydrogenation and oxidation catalysis. Modeling of the contact line of the silica precursor infiltrating into the assembled raspberry colloids suggests that a large part of the particles must be embedded into silica, which is confirmed by quantitative visualization of \>200\ individual NPs by dual-axis electron tomography. The RCT catalysts have a unique structure in which all NPs reside at the pore wall but have \>50\%\ of their surface embedded in the matrix, giving rise to the strongly enhanced thermal and mechanical stability. Importantly, epitaxial overgrowth of Ag on the supported NPs reveals that not only the NP surface exposed to the pore but the embedded interface as well remained chemically accessible. This mechanistic understanding provides valuable guidance in the design of stable catalytic materials.

}, url = {https://onlinelibrary.wiley.com/doi/epdf/10.1002/adfm.202106876}, author = {van der Hoeven, J and Kr{\"a}mer, S. and Dussi, S. and Shirman, T. and Park, K and Rycroft, C and Bell, D and Friend, C and Aizenberg, J.} } @article {1415766, title = {Controlling Liquid Crystal Orientations for Programmable Anisotropic Transformations in Cellular Microstructures}, journal = {Advanced Materials}, year = {2021}, pages = {2105024}, abstract = {

Geometric reconfigurations in cellular structures have recently been exploited to realize adaptive materials with applications in mechanics, optics, and electronics. However, the achievable symmetry breakings and corresponding types of deformation and related functionalities have remained rather limited, mostly due to the fact that the macroscopic geometry of the structures is generally co-aligned with the molecular anisotropy of the constituent material. To address this limitation, cellular microstructures are fabricated out of liquid crystalline elastomers (LCEs) with an arbitrary, user-defined liquid crystal (LC) mesogen orientation encrypted by a weak magnetic field. This platform enables anisotropy to be programmed independently at the molecular and structural levels and the realization of unprecedented director-determined symmetry breakings in cellular materials, which are demonstrated by both finite element analyses and experiments. It is illustrated that the resulting mechanical reconfigurations can be harnessed to program microcellular materials with switchable and direction-dependent frictional properties and further exploit {\textquotedblright}area-specific{\textquotedblright} deformation patterns to locally modulate transmitted light and precisely guide object movement. As such, the work provides a clear route to decouple anisotropy at the materials level from the directionality of the macroscopic cellular structure, which may lead to a new generation of smart and adaptive materials and\ devices.

}, author = {S Li and Librandi, G and Y Yao and Richard, A and Yamamura, A. S and Aizenberg, J and Bertoldi, K.} } @article {1413459, title = {Microscopic origins of the crystallographically preferred growth in evaporation-induced colloidal crystals}, journal = {Proceedings of the National Academy of Sciences}, volume = {118}, year = {2021}, pages = {e2107588118}, abstract = {

Self-assembly is one of the central themes in biologically controlled synthesis, and it also plays a pivotal role in fabricating a variety of advanced engineering materials. In particular, evaporation-induced self-assembly of colloidal particles enables versatile fabrication of highly ordered two- or three-dimensional nanostructures for optical, sensing, catalytic, and other applications. While it is well known that this process results in the formation of the face-centered cubic (fcc) lattice with the close-packed {111} plane parallel to the substrate, the crystallographic texture development of colloidal crystals is less understood. In this study, we show that the preferred \<110\> growth in the fcc colloidal crystals synthesized through evaporation-induced assembly is achieved through a gradual crystallographic rotation facilitated by mechanical stress-induced geometrically necessary dislocations.

}, url = {https://www.pnas.org/content/118/32/e2107588118.short}, author = {Li, Ling and Goodrich, Carl and Yang, Haizhao and Phillips, Katherine R and Jia, Zian and Chen, Hongshun and Wang, Lifeng and Zhang, Jinjin and Liu, Anhua and Lu, Jianfeng and Shuai, Jianwei and Brenner, Michael and Spaepen, Frans and Aizenberg, Joanna} } @article {1413458, title = {Microstructural design for mechanical{\textendash}optical multifunctionality in the exoskeleton of the flower beetle Torynorrhina flammea}, journal = {Proceedings of the National Academy of Sciences}, volume = {118}, year = {2021}, pages = {e2101017118}, abstract = {

In the design of multifunctional materials, harnessing structural and compositional synergies while avoiding unnecessary trade-offs is critical in achieving high performance of all required functions. Biological material systems like the cuticles of many arthropods often fulfill multifunctionality through the intricate design of material structures, simultaneously achieving mechanical, optical, sensory, and other vital functionalities. A better understanding of the structural basis for multifunctionality and the functional synergies and trade-offs in biological materials could thus provide important insights for the design of bioinspired multifunctional materials. In this study, we demonstrate a concerted experimental, theoretical, and computational approach that uncovers the structure{\textendash}mechanics{\textendash}optics relationship of the beetle{\textquoteright}s cuticle, opening avenues to investigate biological materials and design photonic materials with robust mechanical performance.

}, url = {https://www.pnas.org/content/118/25/e2101017118.short}, author = {Jia, Zian and Fernandes, Matheus C. and Deng, Zhifeng and Yang, Ting and Zhang, Qiuting and Lethbridge, Alfie and Yin, Jie and Lee, Jae-Hwang and Han, Lin and Weaver, James and Bertoldi, Katia and Aizenberg, Joanna and Kolle, Mathias and Vukusic, Pete and Li, Ling} } @article {1413457, title = {Dilute Pd-in-Au alloy RCT-SiO2 catalysts for enhanced oxidative methanol coupling}, journal = {Journal of Catalysis}, year = {2021}, abstract = {

Dilute alloy catalysts have the potential to enhance selectivity and activity for large-scale reactions. Highly dilute Pd-in-Au nanoparticle alloys partially embedded in porous silica ({\textquotedblleft}raspberry colloid templated{\textquotedblright} (RCT)-SiO2) prove to be robust and selective catalysts for oxidative coupling of methanol. Palladium concentrations in the bimetallic nanoparticles as low as ~3.4 at.\% catalyze the production of methyl formate with a selectivity of ~95\% at conversions of ~55\%, whereas conversions are low (\<10\%) for ~1.7 at.\% Pd-in-Au nanoparticle and pure Au nanoparticle catalysts. Fractional reaction orders for both CH3OH and O2measured for ~3.4 at.\% Pd-in-Au nanoparticles supported on RCT-SiO2\ indicated a complex mechanism in which the sites for O2\ dissociation are not saturated. Optimal methyl formate production was found for an equimolar mixture. There is no conversion of methanol in the absence of O2\ between 360 and 450\ K. All observations are consistent with a mechanism derived from model studies, requiring that clusters of Pd be available on the catalyst for O2\ dissociation.

}, url = {https://www.sciencedirect.com/science/article/pii/S0021951721002396}, author = {Filie, Amanda and Shirman, Tanya and Foucher, Alexandre C. and Stach, Eric A. and Aizenberg, Michael and Aizenberg, Joanna and Friend, Cynthia M and Madix, Robert J} } @article {1413456, title = {Entropic Control of HD Exchange Rates over Dilute Pd-in-Au Alloy Nanoparticle Catalysts}, journal = {ACS Catalysis}, volume = {11}, year = {2021}, pages = {6971-6981}, abstract = {

Dilute Pd-in-Au alloy catalysts are promising materials for selective hydrogenation catalysis. Extensive surface science studies have contributed mechanistic insight on the energetic aspect of hydrogen dissociation, migration, and recombination on dilute alloy systems. Yet, translating these fundamental concepts to the kinetics and free energy of hydrogen dissociation on nanoparticle catalysts operating at ambient pressures and temperatures remains challenging. Here, the effect of the Pd concentration and Pd ensemble size on the catalytic activity, apparent activation energy, and rate-limiting process is addressed by combining experiment and theory. Experiments in a flow reactor show that a compositional change from 4 to 8 atm\% Pd of the Pd-in-Au alloy catalyst leads to a strong increase in activity, even exceeding the activity per Pd atom of monometallic Pd under the same conditions, albeit with an increase in apparent activation energy. First-principles calculations show that the rate and apparent activation enthalpy for HD exchange increase when increasing the Pd ensemble size from single Pd atoms to Pd trimers in a Au surface, suggesting that the ensemble size distribution shifts from mainly single Pd atoms on the 4 atm\% Pd alloy to larger Pd ensembles of at least three atoms for the 8 atm\% Pd/Au catalyst. The DFT studies also indicated that the rate-controlling process is different: H2\ (D2) dissociation determines the rate for single atoms, whereas recombination of adsorbed H and D determines the rate on Pd trimers, similar to bulk Pd. Both experiment and theory suggest that the increased reaction rate with increasing Pd content and ensemble size stems from an entropic driving force. Finally, our results support hydrogen migration between Pd sites via Au and indicate that the dilute alloy design prevents the formation of subsurface hydrogen, which is crucial in achieving high selectivity in hydrogenation catalysis.

}, url = {https://pubs.acs.org/doi/abs/10.1021/acscatal.1c01400}, author = {van der Hoeven, Jessi ES and Ngan, Hio Tong and Taylor, Austin and Eagan, Nathaniel M and Aizenberg, Joanna and Sautet, Philippe and Madix, Robert J and Friend, Cynthia M} } @article {1413455, title = {Enhanced condensation heat transfer using porous silica inverse opal coatings on copper tubes}, journal = {Scientific Reports}, volume = {11}, year = {2021}, pages = {1-11}, abstract = {

Phase-change condensation is commonplace in nature and industry. Since the 1930s, it is well understood that vapor condenses in filmwise mode on clean metallic surfaces whereas it condenses by forming discrete droplets on surfaces coated with a promoter material. In both filmwise and dropwise modes, the condensate is removed when gravity overcomes pinning forces. In this work, we show rapid condensate transport through cracks that formed due to material shrinkage when a copper tube is coated with silica inverse opal structures. Importantly, the high hydraulic conductivity of the cracks promote axial condensate transport that is beneficial for condensation heat transfer. In our experiments, the cracks improved the heat transfer coefficient from ≈ 12\ kW/m2\ K for laminar filmwise condensation on smooth clean copper tubes to ≈ 80\ kW/m2\ K for inverse opal coated copper tubes; nearly a sevenfold increase from filmwise condensation and identical enhancement with state-of-the-art dropwise condensation. Furthermore, our results show that impregnating the porous structure with oil further improves the heat transfer coefficient by an additional 30\% to ≈ 103\ kW/m2\ K. Importantly, compared to the fast-degrading dropwise condensation, the inverse opal coated copper tubes maintained high heat transfer rates when the experiments were repeated \> 20 times; each experiment lasting 3{\textendash}4\ h. In addition to the new coating approach, the insights gained from this work present a strategy to minimize oil depletion during condensation from lubricated surfaces.

}, url = {https://www.nature.com/articles/s41598-021-90015-x}, author = {Adera, Solomon and Naworski, Lauren and Davitt, Alana and Mandsberg, Nikolaj and Shneidman, Anna V and Jack Alvarenga and Aizenberg, Joanna} } @article {1413451, title = {Bioinspired Soft Microactuators}, journal = {Advanced Materials Interfaces}, volume = {33}, year = {2021}, pages = {2008558}, abstract = {Soft actuators have the potential of revolutionizing the field of robotics. However, it has been a long-standing challenge to achieve simultaneously: i) miniaturization of soft actuators, ii) high contrast between materials properties at their {\textquotedblleft}on{\textquotedblright} and {\textquotedblleft}off{\textquotedblright} states, iii) significant actuation for high-payload mechanical work, and iv) ability to perform diverse shape transformations. This challenge is addressed by synergistically utilizing structural concepts found in the dermis of sea cucumbers and the tendrils of climbing plants, together with microfluidic fabrication to create diatomite-laden hygroscopically responsive fibers with a discontinuous ribbon of stiff, asymmetrically shaped, and hygroscopically inactive microparticles embedded inside. The microactuators can undergo various deformations and have very high property contrast ratios (20{\textendash}850 for various mechanical characteristics of interest) between hydrated and dehydrated states. The resulting energy density, actuation strain, and actuation stress are shown to exceed those of natural muscle by ≈4, \>2, and \>30 times, respectively, and their weight-lifting ratio is 2{\textendash}3 orders of magnitude higher than the value of recent hygroscopic actuators. This work offers a new and general way to design and fabricate next-generation soft microactuators, and thus advances the field of soft robotics by tailoring the structure and properties of deformable elements to suit a desired application.}, url = {https://onlinelibrary.wiley.com/doi/full/10.1002/adma.202008558}, author = {Zhu, Pingan and Chen, Rifei and Zhou, Chunmei and Aizenberg, Michael and Aizenberg, Joanna and Wang, Liqiu} } @article {1413449, title = {Slippery Liquid-Infused Porous Surfaces (SLIPS) for Cell Deformation Enabling Intracellular Cargo Delivery}, journal = {MOLECULAR THERAPY}, volume = {29}, year = {2021}, pages = {233}, author = {Frost, Isaura M. and Mendoza, Alexandra and Chiou, Tzu-Ting and Wattanatorn, Natcha and Zhao, Chuanzhen and Yang, Qing and Kim, Philseok and Aizenberg, Joanna and De Oliveira, Satiro and Weiss, Paul S. and Jonas, Steven J} } @article {1413446, title = {Liquid-induced topological transformations of cellular microstructures}, journal = {Nature }, volume = {592}, year = {2021}, pages = {386-391}, abstract = {

The fundamental topology of cellular structures{\textemdash}the location, number and connectivity of nodes and compartments{\textemdash}can profoundly affect their acoustic,\ electrical, chemical,\ mechanical,\ and optical\ properties, as well as heat, fluid\ and particle transport. Approaches that harness swelling, electromagnetic actuation\ and mechanical instabilities\ in cellular materials have enabled a variety of interesting wall deformations and compartment shape alterations, but the resulting structures generally preserve the defining connectivity features of the initial topology. Achieving topological transformation presents a distinct challenge for existing strategies: it requires complex reorganization, repacking, and coordinated bending, stretching and folding, particularly around each node, where elastic resistance is highest owing to connectivity. Here we introduce a two-tiered dynamic strategy that achieves systematic reversible transformations of the fundamental topology of cellular microstructures, which can be applied to a wide range of materials and geometries. Our approach requires only exposing the structure to a selected liquid that is able to first infiltrate and plasticize the material at the molecular scale, and then, upon evaporation, form a network of localized capillary forces at the architectural scale that {\textquoteleft}zip{\textquoteright} the edges of the softened lattice into a new topological structure, which subsequently restiffens and remains kinetically trapped. Reversibility is induced by applying a mixture of liquids that act separately at the molecular and architectural scales (thus offering modular temporal control over the softening{\textendash}evaporation{\textendash}stiffening sequence) to restore the original topology or provide access to intermediate modes. Guided by a generalized theoretical model that connects cellular geometries, material stiffness and capillary forces, we demonstrate programmed reversible topological transformations of various lattice geometries and responsive materials that undergo fast global or localized deformations. We then harness dynamic topologies to develop active surfaces with information encryption, selective particle trapping and bubble release, as well as tunable mechanical, chemical and acoustic properties.

}, url = {https://www.nature.com/articles/s41586-021-03404-7}, author = {Li, Shucong and Deng, Bolei and Alison Grinthal and Schneider-Yamamura, Alyssa and Kang, Jinliang and Martens, Reese S and Zhang, Cathy T and Li, Jian and Yu, Siqin and Bertoldi, Katia and Aizenberg, Joanna} } @article {1413443, title = {Why Are Water Droplets Highly Mobile on Nanostructured Oil-Impregnated Surfaces?}, journal = {ACS Applied Materials \& Interfaces}, volume = {13}, year = {2021}, pages = {15901-15909}, abstract = {

Porous lubricated surfaces (aka slippery liquid-infused porous surfaces, SLIPS) have been demonstrated to repel various liquids. The origin of this repellency, however, is not fully understood. By using surface-sensitive sum frequency generation vibrational spectroscopy, we characterized the water/oil interface of a water droplet residing on (a) an oil-impregnated nanostructured surface (SLIPS) and (b) the same oil layer without the underlying nanostructures. Different from water molecules in contact with bulk oil without nanostructures, droplets on SLIPS adopt a molecular orientation that is predominantly parallel to the water/oil interface, leading to weaker hydrogen bonding interactions between water droplets and the lubrication film, giving SLIPS their water repellency. Our results demonstrate that the molecular interactions between two contacting liquids can be manipulated by the implementation of nanostructured substrates. The results also offer the molecular principles for controlling nanostructure to reduce oil depletion{\textemdash}one of the limitations and major concerns of SLIPS.

}, url = {https://pubs.acs.org/doi/abs/10.1021/acsami.1c01649}, author = {Zhang, Chengcheng and Adera, Solomon and Aizenberg, Joanna and Chen, Zhan} } @article {1413442, title = {Inverse Opal Films for Medical Sensing: Application in Diagnosis of Neonatal Jaundice}, journal = {Advanced Healthcare Materials}, volume = {10}, year = {2021}, pages = {2001326}, abstract = {

A non-invasive, at-home test for neonatal jaundice can facilitate early jaundice detection in infants, improving clinical outcomes for neonates with severe jaundice and helping to prevent the development of kernicterus, a type of brain damage whose symptoms include hearing loss, impairment of cognitive capacity, and death. Here a photonic sensor that utilizes color changes induced by analyte infiltration into a chemically functionalized inverse opal structure is developed. The sensor is calibrated to detect differences in urinary surface tension due to increased bile salt concentration in urine, which is symptomatic of abnormal liver function and linked to jaundice. The correlation between neonatal urinary surface tension and excess serum bilirubin, the physiologic cause of neonatal jaundice, is explored. It is shown that these non-invasive sensors can improve the preliminary diagnosis of neonatal jaundice, reducing the number of invasive blood tests and hospital visits necessary for healthy infants while ensuring that jaundiced infants are treated in a timely manner. The use of inverse opal sensors to measure bulk property changes in bodily fluids can be extended to the detection of several other conditions, making this technology a versatile platform for convenient point-of-care diagnosis.

}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adhm.202001326}, author = {Nicolas, Natalie and Duffy, Meredith A. and Hansen, Anne and Aizenberg, Joanna} } @article {1413441, title = {Mechanically robust lattices inspired by deep-sea glass sponges}, journal = {Nature Materials}, volume = {20}, year = {2021}, pages = {237-241}, abstract = {

The predominantly deep-sea hexactinellid sponges are known for their ability to construct remarkably complex skeletons from amorphous hydrated silica. The skeletal system of one such species of sponge,\ Euplectella aspergillum, consists of a square-grid-like architecture overlaid with a double set of diagonal bracings, creating a chequerboard-like pattern of open and closed cells. Here, using a combination of finite element simulations and mechanical tests on 3D-printed specimens of different lattice geometries, we show that the sponge{\textquoteright}s diagonal reinforcement strategy achieves the highest buckling resistance for a given amount of material. Furthermore, using an evolutionary optimization algorithm, we show that our sponge-inspired lattice geometry approaches the optimum material distribution for the design space considered. Our results demonstrate that lessons learned from the study of sponge skeletal systems can be exploited for the realization of square lattice geometries that are geometrically optimized to avoid global structural buckling, with implications for improved material use in modern infrastructural applications.

}, url = {https://www.nature.com/articles/s41563-020-0798-1}, author = {Fernandes, Matheus and Aizenberg, Joanna and Weaver, James and Bertoldi, Katia} } @article {1413440, title = {Designing angle-independent structural colors using Monte Carlo simulations of multiple scattering}, journal = {Proceedings of the National Academy of Sciences}, volume = {118}, year = {2021}, pages = {e2015551118}, abstract = {

Disordered nanostructures with correlations on the scale of visible wavelengths can show angle-independent structural colors. These materials could replace dyes in some applications because the color is tunable and resists photobleaching. However, designing nanostructures with a prescribed color is difficult, especially when the application{\textemdash}cosmetics or displays, for example{\textemdash}requires specific component materials. A general approach to solving this constrained design problem is modeling and optimization: Using a model that predicts the color of a given system, one optimizes the model parameters under constraints to achieve a target color. For this approach to work, the model must make accurate predictions, which is challenging because disordered nanostructures have multiple scattering. To address this challenge, we develop a Monte Carlo model that simulates multiple scattering of light in disordered arrangements of spherical particles or voids. The model produces quantitative agreement with measurements when we account for roughness on the surface of the film, particle polydispersity, and wavelength-dependent absorption in the components. Unlike discrete numerical simulations, our model is parameterized in terms of experimental variables, simplifying the connection between simulation and fabrication. To demonstrate this approach, we reproduce the color of the male mountain bluebird (Sialia currucoides) in an experimental system, using prescribed components and a microstructure that is easy to fabricate. Finally, we use the model to find the limits of angle-independent structural colors for a given system. These results enable an engineering design approach to structural color for many different applications.

}, url = {https://www.pnas.org/content/118/4/e2015551118.short}, author = {Hwang, Victoria and Stephenson, Anna and Barkley, Solomon and Brandt, Soeren and Xiao, Ming and Aizenberg, Joanna and Manoharan, Vinothan N} } @article {1413438, title = {Raspberry colloid-templated approach for the synthesis of palladium-based oxidation catalysts with enhanced hydrothermal stability and low-temperature activity}, journal = {Catalysis Today}, volume = {360}, year = {2021}, pages = {241-251}, abstract = {

It is becoming increasingly urgent to develop and utilize novel, more efficient and stable materials for mobile and stationary emission control applications as the deleterious consequences of anthropogenic air pollution are becoming more evident and pressing. Tightening regulations, particularly related to automotive exhaust treatment, together with continued improvements in engine design, that result in lowering the engine operating temperatures and inadvertently lead to the release of an overwhelming proportion of pollutants during the cold start, present new challenges for materials design, specifically for oxidation catalysts. In particular, improvements in the low-temperature activity while maintaining catalyst stability at high temperatures are required from the next-generation catalyst. Typical catalysts for removal of pollutants from automotive exhaust streams incorporate platinum group metals (PGMs). They tend to be inefficient at low temperatures (below 250 {\textdegree}C), thus accounting for the cold start problem, yet sinter and lose their activity at high temperatures that are frequently encountered during catalyst operation. High PGM loadings are often employed to compensate for catalyst inefficiencies and fast degradation, ultimately resulting in high-cost catalytic converters. We have developed a new approach for the design and formation of catalytic materials that allows for both significantly more efficient PGM incorporation and improved overall catalyst performance at reduced PGM loadings. The method provides control over the composition and geometry of the support through self-assembly of sacrificial composite template {\textemdash} {\textquotedblleft}raspberry{\textquotedblright} polymeric colloids decorated with catalytic particles {\textemdash} accompanied by infiltration with metal-oxide precursor and subsequent removal of the colloids. This method simultaneously structures the porous network and organizes the catalytic particles within it. Uniquely, the resulting catalytic particles are partially embedded in the support matrix and partially exposed to the pore interior, producing catalytic sites that are both stable and accessible. Herein, the feasibility of this novel and versatile approach for automotive catalytic conversion is demonstrated: the studies include testing alumina-based raspberry-colloid-templated (RCT) catalysts containing Pd nanoparticles (RCT Pd/Al2O3) for oxidation of propane and carbon monoxide under simulated diesel exhaust conditions and hydrothermal aging at 800 {\textdegree}C for 50 h in the simulated stream. The RCT Pd/Al2O3\ catalysts exhibit exceptional activity toward CO oxidation, reduced reaction onset temperature, and high stability to elevated temperatures (demonstrated through prolonged exposure to temperatures up to 950 {\textdegree}C) and reactive gas streams, without migration, sintering or loss of the precious metal NPs. Notably, the novel catalyst shows the same or slightly better performance than the commercial catalysts even when the PGM load is reduced by \~{}80 \% compared to the commercial counterparts. These results provide confidence for the utilization of the RCT approach for the fabrication of robust nanostructured catalysts for next-generation, energy-efficient catalytic converters with improved performance at low and high temperatures and reduced costs. The RCT methodology is, in addition, highly generalizable, and can thus be applied for the design of a wide range of catalytic systems in the automotive sector and beyond.

}, url = {https://www.sciencedirect.com/science/article/pii/S0920586120301541}, author = {Shirman, Tanya and Toops, Todd J and Shirman, Elijah and Shneidman, Anna V and Liu, Sissi and Gurkin, Keeve and Jack Alvarenga and Lewandowski, Michael and Aizenberg, Michael and Aizenberg, Joanna} } @article {1413436, title = {Controllable growth of interpenetrating or random copolymer networks }, journal = {Soft Matter}, volume = {17}, year = {2021}, pages = {7177-7187}, abstract = {

Interpenetrating and random copolymer networks are vital in a number of industrial applications, including the fabrication of automotive parts, damping materials, and tissue engineering scaffolds. We develop a theoretical model for a process that enables the controlled growth of interpenetrating network (IPNs), or a random copolymer network (RCN) of specified size and mechanical properties. In this process, a primary gel {\textquotedblleft}seed{\textquotedblright} is immersed into a solution containing the secondary monomer and crosslinkers. After the latter species are absorbed into the primary network, the absorbed monomers are polymerized to form the secondary polymer chains, which then can undergo further crosslinking to form an IPN, or undergo inter-chain exchange with the existing network to form a RCN. The swelling and elastic properties of the IPN and RCN networks can be tailored by modifying the monomer and crosslinker concentrations in the surrounding solution, or by tuning the enthalpic interactions between the primary polymer, secondary monomer and solvent through a proper choice of chemistry. This process can be used repeatedly to fabricate gels with a range of mechanical properties from stiff, rigid materials to soft, flexible networks, allowing the method to meet the materials requirements of a variety of applications.

}, url = {https://pubs.rsc.org/en/content/articlelanding/2021/SM/D1SM00611H}, author = {Chatterjee, Rayan and Biswas, Santidan and Yashin, Victor V. and Aizenberg, Michael and Aizenberg, Joanna and Balazs, Anna C} } @article {1413435, title = {The dynamic behavior of dilute metallic alloy Pd x Au 1- x/SiO 2 raspberry colloid templated catalysts under CO oxidation}, journal = {Catalysis Science \& Technology}, year = {2021}, pages = {4072-4082}, abstract = {

Dilute palladium-in-gold alloys have potential as efficient oxidation catalysts; controlling the Pd surface distribution is critical. Here, the activity for CO oxidation catalyzed by robust dilute Pd-in-Au nanoparticles supported on raspberry-colloid-templated (RCT) silica depends on the pretreatment and gas environment. The activities of oxygen-pretreated catalysts are different in light-off studies\ versus\ after long-term use. Transient increases in activity are also induced by flowing CO/He at 553 K. Altogether, these results indicate changes in Pd distribution at the surface induced by reactive gases and that light-off studies alone are not adequate for evaluation of alloy catalyst performance. Kinetic studies show evidence of both isolated and multiple Pd atoms. A dual-site mechanism is operative over Pd0.02Au0.98\ RCT-SiO2, whereas a single-site mechanism governs reaction over Pd0.10Au0.90\ RCT-SiO2. The distinct mechanisms suggest that tuning the ratio of isolated to clustered Pd sites is possible, underscoring the importance of characterization under reaction conditions.

}, url = {https://pubs.rsc.org/en/content/articlelanding/2021/CY/D1CY00469G}, author = {Filie, Amanda and Shirman, Tanya and Aizenberg, Michael and Aizenberg, Joanna and Friend, Cynthia M. and Madix, Robert J.} } @article {1413432, title = {Self-Stratifying Porous Silicones with Enhanced Liquid Infusion and Protective Skin Layer for Biofouling Prevention}, journal = {Advanced Materials Interfaces}, volume = {8}, year = {2021}, pages = {2000359}, abstract = {

Liquid-infused silicones are a promising solution for common surface adhesion problems, such as ice accumulation and biofilm formation, yet they generally lack the tunability, mechanical durability and/or longevity essential for industrial applications. Self-stratifying porous silicones (SPS) infused with compatible silicone oil are developed as a passive strategy to address these shortcomings. Through emulsion templating, porosity is formed in the bulk polymer, providing increased free volume for oil infusion, while a non-porous skin layer is formed at the surface. The bulk porosity and pore size distribution of SPS are independently controlled by varying water and surfactant concentration respectively, leading to a higher volume of oil infusion and improved oil retention relative to an unmodified silicone. Despite a higher oil loading and bulk porosity, the skin layer provides liquid-infused SPS with a comparable surface elasticity to liquid-infused silicones. The potential of liquid-infused SPS as a nontoxic fouling release coating for marine applications is demonstrated using laboratory assays against a variety of soft and hard fouling organisms.

}, url = {https://onlinelibrary.wiley.com/doi/full/10.1002/admi.202000359}, author = {Vena, Alex and Kolle, Stefan and Stafslien, Shane and Aizenberg, Joanna and Kim, Philseok} } @article {1413428, title = {Tunable infrared transmission for energy-efficient pneumatic building fa{\c c}ades}, journal = {Energy and Buildings}, year = {2020}, pages = {110377}, abstract = {

Thermal regulation of buildings in climates with daily and seasonal weather changes can prove challenging and result in high building energy consumption. While adaptable fa{\c c}ades with tunable infrared transmitting properties could modulate solar transmittance through the building envelope and, as such, increase energy efficiency, available technologies to meet these needs are often expensive, relatively complicated, and challenging to implement in a lightweight form factor.

Motivated by these limitations, this report presents a novel tunable light-modulating technology for energy-efficient pneumatic fa{\c c}ades in the form of polydimethylsiloxane (PDMS) film with a thin gold surface coating. Sequential stretching and relaxing of this film results in strain-induced microscale surface cracks that can significantly modulate both visible and near infrared light transmission, and consequently, the material{\textquoteright}s solar heat gain coefficient (SHGC).

The material{\textquoteright}s tunability has shown a significant potential to reduce building energy use, as assessed with building simulation software. The technology offers additional advantages for light modulation in pneumatic fa{\c c}ades including real-time operation, ease of implementation and control, and predictable performance. Fa{\c c}ade design guidelines for the integration of the infrared-regulating film into ethylene tetrafluoroethylene (ETFE) building envelopes and climate suitability are described, and a critical evaluation of material durability, optical clarity, and material costs are provided.

}, url = {https://www.sciencedirect.com/science/article/pii/S0378778819331469?via\%3Dihub}, author = {Tomholt, Lara and Geletina, Olga and Jack Alvarenga and Shneidman, Anna. V and Weaver, James C. and Fernandes, Matheus C. and Mota, Santiago A. and Martin Bechthold and Aizenberg, Joanna} } @article {1413426, title = {Depletion of Lubricant from Nanostructured Oil-Infused Surfaces by Pendant Condensate Droplets}, journal = {ACS Nano}, volume = {14}, year = {2020}, pages = {8024{\textendash}8035}, abstract = {

Due to recent advances in nanofabrication, phase-change condensation heat transfer has seen a renaissance. Compared to conventional heat transfer surfaces, nanostructured surfaces impregnated with chemically matched lubrication films (hereinafter referred to as {\textquotedblleft}nanostructured lubricated surfaces{\textquotedblright}) have been demonstrated to improve vapor-side phase-change condensation heat transfer by facilitating droplet nucleation, growth, and departure. While the presence of nanoscale roughness improves performance longevity by stabilizing the lubrication film\ via\ capillary forces, such enhancement is short-lived due to the eventual loss of lubrication oil by the departing droplets. The objective of this study is to characterize oil depletion caused by pendant droplets during condensation. For our study, we nanostructured, chemically functionalized, and lubricated horizontal copper tubes that are widely used in shell-and-tube heat exchangers in power plants and process industries. Using high-speed fluorescence imaging and thermogravimetric analysis, we show that shedding droplets exert a shear force on the oil in the wetting ridge at the water{\textendash}oil interface. The viscous shear draws the lubrication film from the nanostructured surface onto the upper portion of the droplet and forms a ring-like oil skirt. Through detailed theoretical analysis, we show that the thickness of this oil skirt scales with the classical Landau{\textendash}Levich{\textendash}Derjaguin (LLD) theory for dip-coating. Our results reveal that droplets falling from horizontal tubes break unequally and leave behind small satellite droplets that retain the bulk of the oil in the wetting ridge. This observation is in stark contrast with the earlier description of droplets shedding from tilted flat plates where the entire oil-filled wetting ridge is demonstrated to leave the surface upon droplet departure. By selecting lubrication oils of varying viscosity and spreading coefficient, we provide evidence that the contribution of the wrapping layer to the rate of oil depletion is insignificant. Furthermore, we show that due to the nanoscale features on the tubes, nearly half of the lubrication film remains on the surface after 10 h of continuous steam condensation at ambient pressure, 23 {\textdegree}C, and 60\% relative humidity, a 2{\textendash}3-fold improvement over previous results.The insights gained from this work will provide guidelines for the rational design of long-lasting nanostructured lubricated surfaces for phase-change condensation.

}, url = {https://pubs.acs.org/doi/abs/10.1021/acsnano.9b10184}, author = {Adera, Solomon and Jack Alvarenga and Shneidman, Anna. V and Zhang, Cathy T and Davitt, Alana and Aizenberg, Joanna} } @article {1413423, title = {Fabrication of Photonic Microbricks via Crack Engineering of Colloidal Crystals}, journal = {Advanced Functional Materials}, year = {2020}, pages = {1908242}, abstract = {

Evaporation-induced self-assembly of colloidal particles is one of the most versatile fabrication routes to obtain large-area colloidal crystals; however, the formation of uncontrolled {\textquotedblleft}drying cracks{\textquotedblright} due to gradual solvent evaporation represents a significant challenge of this process. While several methods are reported to minimize crack formation during evaporation-induced colloidal assembly, here an approach is reported to take advantage of the crack formation as a patterning tool to fabricate microscopic photonic structures with controlled sizes and geometries. This is achieved through a mechanistic understanding of the fracture behavior of three different types of opal structures, namely, direct opals (colloidal crystals with no matrix material), compound opals (colloidal crystals with matrix material), and inverse opals (matrix material templated by a sacrificial colloidal crystal). This work explains why, while direct and inverse opals tend to fracture along the expected {111} planes, the compound opals exhibit a different cracking behavior along the nonclose-packed {110} planes, which is facilitated by the formation of cleavage-like fracture surfaces. The discovered principles are utilized to fabricate photonic microbricks by programming the crack initiation at specific locations and by guiding propagation along predefined orientations during the self-assembly process, resulting in photonic microbricks with controlled sizes and geometries.

}, url = {https://onlinelibrary.wiley.com/doi/full/10.1002/adfm.201908242}, author = {Katherine R. Phillips and Zhang, Cathy T. and Yang, Ting and Kay, Theresa and Gao, Chao and Brandt, Soeren and Liu, Lei and Yang, Haizhao and Li, Yaning and Aizenberg, Joanna and Li, Ling} } @article {1413419, title = {Neural network assisted analysis of bimetallic nanocatalysts using X-ray absorption near edge structure spectroscopy}, journal = {Physical Chemistry Chemical Physics}, year = {2020}, pages = {18902-18910}, abstract = {

X-ray absorption spectroscopy is a common method for probing the local structure of nanocatalysts. One portion of the X-ray absorption spectrum, the X-ray absorption near edge structure (XANES) is a useful alternative to the commonly used extended X-ray absorption fine structure (EXAFS) for probing three-dimensional geometry around each type of atomic species, especially in those cases when the EXAFS data quality is limited by harsh reaction conditions and low metal loading. A methodology for quantitative determination of bimetallic architectures from their XANES spectra is currently lacking. We have developed a method, based on the artificial neural network, trained on\ ab initio\ site-specific XANES calculations, that enables accurate and rapid reconstruction of the structural descriptors (partial coordination numbers) from the experimental XANES data. We demonstrate the utility of this method on the example of a series of PdAu bimetallic nanoalloys. By validating the neural network-yielded metal{\textendash}metal coordination numbers based on the XANES analysis by previous EXAFS characterization, we obtained new results for\ in situ\ restructuring of dilute (2.6 at\% Pd in Au) PdAu nanoparticles, driven by their gas and temperature treatments.


\ }, url = {https://pubs.rsc.org/en/content/articlelanding/2020/CP/D0CP02098B}, author = {Marcella, N. and Liu, Yang and Janis Timoshenko and Guan, Erija and Luneau, Mathilde and Shirman, Tanya and Plonka, Anna M. and van der Hoeven, Jessi E. S. and Aizenberg, Joanna and Cynthia Friend and Frenkel, Anatoly I.} } @article {1383296, title = {Tunable Long-Range Interactions between Self-Trapped Beams driven by the Thermal Response of Photoresponsive Hydrogels}, journal = {Chemistry of MaterialsChemistry of Materials}, year = {2020}, note = {doi: 10.1021/acs.chemmater.0c03702}, month = {2020}, publisher = {American Chemical Society}, isbn = {0897-4756}, url = {https://doi.org/10.1021/acs.chemmater.0c03702}, author = {Meeks, Amos and Mac, Rebecca and Chathanat, Simran and Aizenberg, Joanna} } @article {1380767, title = {Dynamic Self-Repairing Hybrid Liquid-in-Solid Protective Barrier for Cementitious Materials}, journal = {ACS Applied Materials \& InterfacesACS Applied Materials \& Interfaces}, volume = {12}, year = {2020}, note = {doi: 10.1021/acsami.0c06357}, month = {2020}, pages = {31922 - 31932}, publisher = {American Chemical Society}, abstract = {Corrosion and surface fouling of structural materials, such as concrete, are persistent problems accelerating undesirable material degradation for many industries and infrastructures. To counteract these detrimental effects, protective coatings are frequently applied, but these solid-based coatings can degrade or become mechanically damaged over time. Such irreversible and irreparable damage on solid-based protective coatings expose underlying surfaces and bulk materials to adverse environmental stresses leading to subsequent fouling and degradation. We introduce a new concept of a hybrid liquid-in-solid protective barrier (LIB) to overcome the limitations of traditional protective coatings with broad applicability to structural materials. Through optimization of capillary forces and reduction of the interfacial energy between an upper mobile liquid and a lower immobile solid phase, a stable liquid-based protective layer is created. This provides a persistent self-repairing barrier against the infiltration of moisture and salt, in addition to omniphobic surface properties. As a model experimental test bed, we applied this concept to cementitious materials, which are commonly used as binders in concrete, and investigated how the mobile liquid phase embedded within a porous solid support contributes to the material{\textquoteright}s barrier protection and antifouling properties. Using industry standard test methods for acid resistance, chloride-ion penetrability, freeze{\textendash}thaw cyclability, and mechanical durability, we demonstrate that LIBs exhibit significantly reduced water absorption and ion penetrability, improved repellency against various nonaqueous liquids, and resistance to corrosion while maintaining their required mechanical performance as structural materials.Corrosion and surface fouling of structural materials, such as concrete, are persistent problems accelerating undesirable material degradation for many industries and infrastructures. To counteract these detrimental effects, protective coatings are frequently applied, but these solid-based coatings can degrade or become mechanically damaged over time. Such irreversible and irreparable damage on solid-based protective coatings expose underlying surfaces and bulk materials to adverse environmental stresses leading to subsequent fouling and degradation. We introduce a new concept of a hybrid liquid-in-solid protective barrier (LIB) to overcome the limitations of traditional protective coatings with broad applicability to structural materials. Through optimization of capillary forces and reduction of the interfacial energy between an upper mobile liquid and a lower immobile solid phase, a stable liquid-based protective layer is created. This provides a persistent self-repairing barrier against the infiltration of moisture and salt, in addition to omniphobic surface properties. As a model experimental test bed, we applied this concept to cementitious materials, which are commonly used as binders in concrete, and investigated how the mobile liquid phase embedded within a porous solid support contributes to the material{\textquoteright}s barrier protection and antifouling properties. Using industry standard test methods for acid resistance, chloride-ion penetrability, freeze{\textendash}thaw cyclability, and mechanical durability, we demonstrate that LIBs exhibit significantly reduced water absorption and ion penetrability, improved repellency against various nonaqueous liquids, and resistance to corrosion while maintaining their required mechanical performance as structural materials.}, isbn = {1944-8244}, url = {https://doi.org/10.1021/acsami.0c06357}, author = {Paink, Gurminder K. and Kolle, Stefan and Le, Duy and Weaver, James C. and Jack Alvarenga and Ahanotu, Onyemaechi and Aizenberg, Joanna and Kim, Philseok} } @article {1313946, title = {Metallic Liquid Gating Membranes}, journal = {ACS NanoACS Nano}, volume = {14}, year = {2020}, note = {doi: 10.1021/acsnano.9b10063}, month = {2020}, pages = {2465 - 2474}, publisher = {American Chemical Society}, isbn = {1936-0851}, url = {https://doi.org/10.1021/acsnano.9b10063}, author = {Alexander B. Tesler and Zhizhi Sheng and Lv, Wei and Fan, Yi and Fricke, David and Kyoo-Chul Park and Jack Alvarenga and Aizenberg, Joanna and Xu Hou} } @article {1313944, title = {Opto-chemo-mechanical transduction in photoresponsive gels elicits switchable self-trapped beams with remote interactions}, journal = {Proceedings of the National Academy of Sciences}, volume = {117}, year = {2020}, month = {2020/02/25}, pages = {3953}, abstract = {Self-trapped light beams hold potential for optical interconnects, applications in image transmission, rerouting light, logic gates for computing and, importantly, for the next-generation light-guiding-light signal processing, which envisions a circuitry-free and reconfigurable photonics powered by the dynamic interactions of self-trapped beams. In conventional nonlinear materials, however, self-trapping suffers from either the need for large incident beam powers and loss of beam interactions at large distances, or it is slow and irreversible. We show that rapidly and repeatably switchable self-trapped laser beams with remote communication capabilities can be elicited at exceptionally small intensities in a pliant, processable hydrogel functionalized with a chromophore. The ability to generate self-trapped beams with this unique set of properties offers unprecedented opportunities to develop light-guiding-light technologies.Next-generation photonics envisions circuitry-free, rapidly reconfigurable systems powered by solitonic beams of self-trapped light and their particlelike interactions. Progress, however, has been limited by the need for reversibly responsive materials that host such nonlinear optical waves. We find that repeatedly switchable self-trapped visible laser beams, which exhibit strong pairwise interactions, can be generated in a photoresponsive hydrogel. Through comprehensive experiments and simulations, we show that the unique nonlinear conditions arise when photoisomerization of spiropyran substituents in pH-responsive poly(acrylamide-co-acrylic acid) hydrogel transduces optical energy into mechanical deformation of the 3D cross-linked hydrogel matrix. A Gaussian beam self-traps when localized isomerization-induced contraction of the hydrogel and expulsion of water generates a transient waveguide, which entraps the optical field and suppresses divergence. The waveguide is erased and reformed within seconds when the optical field is sequentially removed and reintroduced, allowing the self-trapped beam to be rapidly and repeatedly switched on and off at remarkably low powers in the milliwatt regime. Furthermore, this opto-chemo-mechanical transduction of energy mediated by the 3D cross-linked hydrogel network facilitates pairwise interactions between self-trapped beams both in the short range where there is significant overlap of their optical fields, and even in the long range{\textendash}{\textendash}over separation distances of up to 10 times the beam width{\textendash}{\textendash}where such overlap is negligible.}, url = {http://www.pnas.org/content/117/8/3953.abstract}, author = {Morim, Derek R. and Meeks, Amos and Shastri, Ankita and Tran, Andy and Anna V. Shneidman and Yashin, Victor V. and Mahmood, Fariha and Balazs, Anna C. and Aizenberg, Joanna and Saravanamuttu, Kalaichelvi} } @article {1313943, title = {Patterning non-equilibrium morphologies in stimuli-responsive gels through topographical confinement}, journal = {Soft Matter}, volume = {16}, year = {2020}, month = {2020}, pages = {1463 - 1472}, publisher = {The Royal Society of Chemistry}, abstract = {Stimuli-responsive {\textquotedblleft}smart{\textquotedblright} polymers have generated significant interest for introducing dynamic control into the properties of antifouling coatings, smart membranes, switchable adhesives and cell manipulation substrates. Switchable surface morphologies formed by confining stimuli-responsive gels to topographically structured substrates have shown potential for a variety of interfacial applications. Beyond patterning the equilibrium swelling behavior of gels, subjecting stimuli-responsive gels to topographical confinement could also introduce spatial gradients in the various timescales associated with gel deformation, giving rise to novel non-equilibrium morphologies. Here we show how by curing poly(N-isopropylacrylamide) (pNIPAAm)-based gel under confinement to a rigid, bumpy substrate, we can not only induce the surface curvature to invert with temperature, but also program the transient, non-equilibrium morphologies that emerge during the inversion process through changing the heating path. Finite element simulations show that the emergence of these transient morphologies is correlated with confinement-induced gradients in polymer concentration and position-dependent hydrostatic pressure within the gel. To illustrate the relevance of such morphologies in interfacial applications, we show how they enable us to control the gravity-induced assembly of colloidal particles and microalgae. Finally, we show how more complex arrangements in particle assembly can be created through controlling the thickness of the temperature-responsive gel over the bumps. Patterning stimuli-responsive gels on topographically-structured surfaces not only enables switching between two invertible topographies, but could also create opportunities for stimuli ramp-dependent control over the local curvature of the surface and emergence of unique transient morphologies. Harnessing these features could have potential in the design of multifunctional, actuatable materials for switchable adhesion, antifouling, cell manipulation, and liquid and particle transport surfaces.}, isbn = {1744-683X}, url = {http://dx.doi.org/10.1039/C9SM02221J}, author = {Zhang, Cathy T. and Liu, Ya and Wang, Xinran and Wang, Xiaoguang and Kolle, Stefan and Balazs, Anna C. and Aizenberg, Joanna} } @article {1313942, title = {3D Printable and Reconfigurable Liquid Crystal Elastomers with Light-Induced Shape Memory via Dynamic Bond Exchange}, journal = {Advanced MaterialsAdvanced MaterialsAdv. Mater.}, volume = {32}, year = {2020}, note = {doi: 10.1002/adma.201905682}, month = {2020}, pages = {1905682}, publisher = {John Wiley \& Sons, Ltd}, abstract = {Abstract 3D printable and reconfigurable liquid crystal elastomers (LCEs) that reversibly shape-morph when cycled above and below their nematic-to-isotropic transition temperature (TNI) are created, whose actuated shape can be locked-in via high-temperature UV exposure. By synthesizing LCE-based inks with light-triggerable dynamic bonds, printing can be harnessed to locally program their director alignment and UV light can be used to enable controlled network reconfiguration without requiring an imposed mechanical field. Using this integrated approach, 3D LCEs are constructed in both monolithic and heterogenous layouts that exhibit complex shape changes, and whose transformed shapes could be locked-in on demand.}, keywords = {3D printing, dynamic covalent bonds, light responsive, liquid crystal elastomers, shape memory}, isbn = {0935-9648}, url = {https://doi.org/10.1002/adma.201905682}, author = {Emily C. Davidson and Arda Kotikian and Li, Shucong and Aizenberg, Joanna and Jennifer A. Lewis} } @article {1313941, title = {New Role of Pd Hydride as a Sensor of Surface Pd Distributions in Pd-Au Catalysts}, journal = {ChemCatChemChemCatChemChemCatChem}, volume = {12}, year = {2020}, note = {doi: 10.1002/cctc.201901847}, month = {2020}, pages = {717 - 721}, publisher = {John Wiley \& Sons, Ltd}, abstract = {Abstract Isolated or contiguous, the surface distributions of Pd atoms in the Pd?Au bimetallic nanoparticle (NP) catalysts often influence activity and selectivity towards specific reactions. In this study, we used a concomitant Pd hydride formation upon H2 exposure as a probe of presence of contiguous Pd regions in bimetallic NPs. For demonstrating this method, we prepared silica supported monometallic Pd and bimetallic Pd?Au NPs with a Pd/Au ratio of 25/75 (Pd25Au75) and used X-ray absorption spectroscopy, scanning transmission electron microscopy and infrared spectroscopy to detect and quantitatively analyze the Pd hydride regions. This work provides a new approach to characterizing intra-particle heterogeneities within the bimetallic NPs at ambient temperature and pressure.}, keywords = {Bimetallic catalysts, Pd hydride, Pd-Au nanoparticles, Surface heterogeneity, X-ray absorption spectroscopy}, isbn = {1867-3880}, url = {https://doi.org/10.1002/cctc.201901847}, author = {Guan, Erjia and Foucher, Alexandre C. and Marcella, Nicholas and Shirman, Tanya and Luneau, Mathilde and Head, Ashley R. and Verbart, David M. A. and Aizenberg, Joanna and Friend, Cynthia M. and Stacchiola, Dario and Stach, Eric A. and Frenkel, Anatoly I.} } @article {1313940, title = {Twist again: Dynamically and reversibly controllable chirality in liquid crystalline elastomer microposts}, journal = {Science Advances}, volume = {6}, year = {2020}, month = {2020/03/01}, pages = {eaay5349}, abstract = {Photoresponsive liquid crystalline elastomers (LCEs) constitute ideal actuators for soft robots because their light-induced macroscopic shape changes can be harnessed to perform specific articulated motions. Conventional LCEs, however, do not typically exhibit complex modes of bending and twisting necessary to perform sophisticated maneuvers. Here, we model LCE microposts encompassing side-chain mesogens oriented along a magnetically programmed nematic director, and azobenzene cross-linkers, which determine the deformations of illuminated posts. On altering the nematic director orientation from vertical to horizontal, the post{\textquoteright}s bending respectively changes from light-seeking to light-avoiding. Moreover, both modeling and subsequent experiments show that with the director tilted at 45{\textdegree}, the initially achiral post reversibly twists into a right- or left-handed chiral structure, controlled by the angle of incident light. We exploit this photoinduced chirality to design {\textquotedblleft}chimera{\textquotedblright} posts (encompassing two regions with distinct director orientations) that exhibit simultaneous bending and twisting, mimicking motions exhibited by the human musculoskeletal system.}, url = {http://advances.sciencemag.org/content/6/13/eaay5349.abstract}, author = {Waters, James T. and Li, Shucong and Yuxing Yao and Lerch, Michael M. and Aizenberg, Michael and Aizenberg, Joanna and Balazs, Anna C.} } @article {1313939, title = {Viewpoint: Homeostasis as Inspiration{\textemdash}Toward Interactive Materials}, journal = {Advanced MaterialsAdvanced MaterialsAdv. Mater.}, volume = {32}, year = {2020}, note = {doi: 10.1002/adma.201905554}, month = {2020}, pages = {1905554}, publisher = {John Wiley \& Sons, Ltd}, abstract = {Abstract Homeostatic systems combine an ability to maintain integrity over time with an incredible capacity for interactive behavior. Fundamental to such systems are building blocks of ?mini-homeostasis?: feedback loops in which one component responds to a stimulus and another opposes the response, pushing the module to restore its original configuration. Particularly when they cross time and length scales, perturbation of these loops by external changes can generate diverse and complex phenomena. Here, it is proposed that by recognizing and implementing mini-homeostatic modules?often composed of very different physical and chemical processes?into synthetic materials, numerous interactive behaviors can be obtained, opening avenues for designing multifunctional materials. How a variety of controlled, nontrivial material responses can be evoked from even simple versions of such synthetic feedback modules is illustrated. Moreover, random events causing seemingly random responses give insights into how one can further explore, understand and control the full interaction space. Ultimately, material fabrication and exploration of interactivity become inseparable in the rational design of such materials. Homeostasis provides a lens through which one can learn how to combine and perturb coupled processes across time and length scales to conjure up exciting behaviors for new materials that are both robust and interactive.}, keywords = {feedback loops, Homeostasis, interactivity, rational design, self-regulation}, isbn = {0935-9648}, url = {https://doi.org/10.1002/adma.201905554}, author = {Lerch, Michael M. and Alison Grinthal and Aizenberg, Joanna} } @article {1313938, title = {Colorimetric Ethanol Indicator Based on Instantaneous, Localized Wetting of a Photonic Crystal}, journal = {ACS Applied Materials \& InterfacesACS Applied Materials \& Interfaces}, volume = {12}, year = {2020}, note = {doi: 10.1021/acsami.9b19836}, month = {2020}, pages = {1924 - 1929}, publisher = {American Chemical Society}, isbn = {1944-8244}, url = {https://doi.org/10.1021/acsami.9b19836}, author = {Yu, Yanhao and Brandt, Soeren and Nicolas, Natalie J. and Aizenberg, Joanna} } @article {1313936, title = {Silica{\textendash}titania hybrids for structurally robust inverse opals with controllable refractive index}, journal = {Journal of Materials Chemistry C}, volume = {8}, year = {2020}, month = {2020}, pages = {109 - 116}, publisher = {The Royal Society of Chemistry}, abstract = {Templated from sacrificial colloidal assemblies, inverse opals are comprised of an interconnected periodic network of pores, forming a photonic crystal. They are used in a variety of applications, most of which, especially those in optics and photocatalysis, require a high degree of control over the long-range order, composition and refractive index. It has been shown that hybrid materials combining different components can yield materials with properties that are superior to the individual components. Here, we describe the assembly of hybrid titania/silica inverse opals using sol{\textendash}gel chemistry, resulting in a mixed oxide with well-dispersed titanium and silicon. Titania has a high refractive index (2.4{\textendash}2.9), but cracks typically form in the inverse opal structure; conversely, silica can produce highly ordered crack-free inverse opals, but it has a lower refractive index (\~{}1.4). By adjusting the ratio of titania and silica, the refractive index can be tailored while minimizing the crack density and maintaining structural order, allowing for control over the optical properties of this hybrid nanoporous material.}, isbn = {2050-7526}, url = {http://dx.doi.org/10.1039/C9TC05103A}, author = {Katherine R. Phillips and Shirman, Tanya and Aizenberg, Michael and England, Grant T. and Vogel, Nicolas and Aizenberg, Joanna} } @article {1313935, title = {Non-equilibrium signal integration in hydrogels}, volume = {11}, year = {2020}, month = {2020}, pages = {386}, abstract = {Materials that perform complex chemical signal processing are ubiquitous in living systems. Their synthetic analogs would transform developments in biomedicine, catalysis, and many other areas. By drawing inspiration from biological signaling dynamics, we show how simple hydrogels have a previously untapped capacity for non-equilibrium chemical signal processing and integration. Using a common polyacrylic acid hydrogel, with divalent cations and acid as representative stimuli, we demonstrate the emergence of non-monotonic osmosis-driven spikes and waves of expansion/contraction, as well as traveling color waves. These distinct responses emerge from different combinations of rates and sequences of~arriving stimuli. A non-equilibrium continuum theory we developed quantitatively captures the non-monotonic osmosis-driven deformation waves and determines the onset of their emergence in terms of the input parameters. These results suggest that~simple hydrogels, already built into numerous systems, have a much larger sensing space than currently employed.}, isbn = {2041-1723}, url = {https://doi.org/10.1038/s41467-019-14114-0}, author = {Korevaar, Peter A. and Kaplan, C. Nadir and Alison Grinthal and Rust, Reanne M. and Aizenberg, Joanna} } @article {1313934, title = {Beyond biotemplating: multiscale porous inorganic materials with high catalytic efficiency}, journal = {Chemical Communications}, volume = {56}, year = {2020}, month = {2020}, pages = {3389 - 3392}, publisher = {The Royal Society of Chemistry}, abstract = {Biotemplating makes it possible to prepare materials with complex structures by taking advantage of nature{\textquoteright}s ability to generate unique morphologies. In this work, we designed and produced a multi-scale porosity (MSP) scaffold starting from sea urchin spines by adding an additional nano-porosity to its native micro-porosity. The final replica shows porosity in both length scales and is an effective high-performing photocatalytic material.}, isbn = {1359-7345}, url = {http://dx.doi.org/10.1039/D0CC00651C}, author = {Magnabosco, Giulia and Papiano, Irene and Aizenberg, Michael and Aizenberg, Joanna and Falini, Giuseppe} } @article {1313933, title = {Enhancing catalytic performance of dilute metal alloy nanomaterials}, volume = {3}, year = {2020}, month = {2020}, pages = {46}, abstract = {Dilute alloys are promising materials for sustainable chemical production; however, their composition and structure affect their performance. Herein, a comprehensive study of the effects of pretreatment conditions on the materials properties of Pd0.04Au0.96 nanoparticles partially embedded in porous silica is related to the activity for catalytic hydrogenation of 1-hexyne to 1-hexene. A combination of in situ characterization and theoretical calculations provide evidence that changes in palladium surface content are induced by treatment in oxygen, hydrogen and carbon monoxide at various temperatures. In turn, there are changes in hydrogenation activity because surface palladium is necessary for H2 dissociation. These Pd0.04Au0.96 nanoparticles in the porous silica remain structurally intact under many cycles of activation and deactivation and are remarkably resistant to sintering, demonstrating that dilute alloy catalysts are highly dynamic systems that can be tuned and maintained in a active state.}, isbn = {2399-3669}, url = {https://doi.org/10.1038/s42004-020-0293-2}, author = {Luneau, Mathilde and Guan, Erjia and Chen, Wei and Foucher, Alexandre C. and Marcella, Nicholas and Shirman, Tanya and Verbart, David M. A. and Aizenberg, Joanna and Aizenberg, Michael and Stach, Eric A. and Madix, Robert J. and Frenkel, Anatoly I. and Friend, Cynthia M.} } @article {1313950, title = {Dilute Pd/Au Alloy Nanoparticles Embedded in Colloid-Templated Porous SiO2: Stable Au-Based Oxidation Catalysts}, journal = {Chemistry of MaterialsChemistry of Materials}, volume = {31}, year = {2019}, note = {doi: 10.1021/acs.chemmater.9b01779}, month = {2019}, pages = {5759 - 5768}, publisher = {American Chemical Society}, isbn = {0897-4756}, url = {https://doi.org/10.1021/acs.chemmater.9b01779}, author = {Luneau, Mathilde and Shirman, Tanya and Filie, Amanda and Janis Timoshenko and Chen, Wei and Trimpalis, Antonios and Flytzani-Stephanopoulos, Maria and Kaxiras, Efthimios and Frenkel, Anatoly I. and Aizenberg, Joanna and Friend, Cynthia M. and Madix, Robert J.} } @article {1313949, title = {Structurally assisted super black in colourful peacock spiders}, journal = {Proceedings of the Royal Society B: Biological SciencesProceedings of the Royal Society B: Biological Sciences}, volume = {286}, year = {2019}, note = {doi: 10.1098/rspb.2019.0589}, month = {2019}, pages = {20190589}, publisher = {Royal Society}, url = {https://doi.org/10.1098/rspb.2019.0589}, author = {McCoy, Dakota E. and McCoy, Victoria E. and Mandsberg, Nikolaj K. and Anna V. Shneidman and Aizenberg, Joanna and Prum, Richard O. and Haig, David} } @article {1313948, title = {Effect of Surface Chemistry on Incorporation of Nanoparticles within Calcite Single Crystals}, journal = {Crystal Growth \& DesignCrystal Growth \& Design}, volume = {19}, year = {2019}, note = {doi: 10.1021/acs.cgd.9b00208}, month = {2019}, pages = {4429 - 4435}, publisher = {American Chemical Society}, isbn = {1528-7483}, url = {https://doi.org/10.1021/acs.cgd.9b00208}, author = {Magnabosco, Giulia and Polishchuk, Iryna and Palomba, Francesco and Rampazzo, Enrico and Prodi, Luca and Aizenberg, Joanna and Pokroy, Boaz and Falini, Giuseppe} } @article {1313947, title = {Wide-Angle Spectrally Selective Absorbers and Thermal Emitters Based on Inverse Opals}, journal = {ACS PhotonicsACS Photonics}, volume = {6}, year = {2019}, note = {doi: 10.1021/acsphotonics.9b00922}, month = {2019}, pages = {2607 - 2611}, publisher = {American Chemical Society}, url = {https://doi.org/10.1021/acsphotonics.9b00922}, author = {Shahsafi, Alireza and Joe, Graham and Brandt, Soeren and Anna V. Shneidman and Stanisic, Nicholas and Xiao, Yuzhe and Wambold, Raymond and Yu, Zhaoning and Salman, Jad and Aizenberg, Joanna and Kats, Mikhail A.} } @article {1313937, title = {Fabrication of Photonic Microbricks via Crack Engineering of Colloidal Crystals}, journal = {Advanced Functional MaterialsAdvanced Functional MaterialsAdv. Funct. Mater.}, volume = {n/a}, year = {2019}, note = {doi: 10.1002/adfm.201908242}, month = {2019}, pages = {1908242}, publisher = {John Wiley \& Sons, Ltd}, abstract = {Abstract Evaporation-induced self-assembly of colloidal particles is one of the most versatile fabrication routes to obtain large-area colloidal crystals; however, the formation of uncontrolled ?drying cracks? due to gradual solvent evaporation represents a significant challenge of this process. While several methods are reported to minimize crack formation during evaporation-induced colloidal assembly, here an approach is reported to take advantage of the crack formation as a patterning tool to fabricate microscopic photonic structures with controlled sizes and geometries. This is achieved through a mechanistic understanding of the fracture behavior of three different types of opal structures, namely, direct opals (colloidal crystals with no matrix material), compound opals (colloidal crystals with matrix material), and inverse opals (matrix material templated by a sacrificial colloidal crystal). This work explains why, while direct and inverse opals tend to fracture along the expected {111} planes, the compound opals exhibit a different cracking behavior along the nonclose-packed {110} planes, which is facilitated by the formation of cleavage-like fracture surfaces. The discovered principles are utilized to fabricate photonic microbricks by programming the crack initiation at specific locations and by guiding propagation along predefined orientations during the self-assembly process, resulting in photonic microbricks with controlled sizes and geometries.}, keywords = {colloidal crystals, fracture, nano/microfabrication, self-assembly}, isbn = {1616-301X}, url = {https://doi.org/10.1002/adfm.201908242}, author = {Katherine R. Phillips and Zhang, Cathy T. and Yang, Ting and Kay, Theresa and Gao, Chao and Brandt, Soeren and Liu, Lei and Yang, Haizhao and Li, Yaning and Aizenberg, Joanna and Li, Ling} } @article {1223556, title = {Designing Liquid-Infused Surfaces for Medical Applications: A Review}, journal = {Advanced MaterialsAdvanced MaterialsAdv. Mater.}, volume = {30}, year = {2018}, note = {doi: 10.1002/adma.201802724}, month = {2018}, pages = {1802724}, publisher = {John Wiley \& Sons, Ltd}, abstract = {Abstract The development of new technologies is key to the continued improvement of medicine, relying on comprehensive materials design strategies that can integrate advanced therapeutic and diagnostic functions with a variety of surface properties such as selective adhesion, dynamic responsiveness, and optical/mechanical tunability. Liquid-infused surfaces have recently come to the forefront as a unique approach to surface coatings that can resist adhesion of a wide range of contaminants on medical devices. Furthermore, these surfaces are proving highly versatile in enabling the integration of established medical surface treatments alongside the antifouling capabilities, such as drug release or biomolecule organization. Here, the range of research being conducted on liquid-infused surfaces for medical applications is presented, from an understanding of the basics behind the interactions of physiological fluids, microbes, and mammalian cells with liquid layers to current applications of these materials in point-of-care diagnostics, medical tubing, instruments, implants, and tissue engineering. Throughout this exploration, the design parameters of liquid-infused surfaces and how they can be adapted and tuned to particular applications are discussed, while identifying how the range of controllable factors offered by liquid-infused surfaces can be used to enable completely new and dynamic approaches to materials and devices for human health.}, keywords = {adaptive materials, antifouling, devices, diagnostics, surface coatings}, isbn = {0935-9648}, url = {https://doi.org/10.1002/adma.201802724}, author = {Howell, Caitlin and Alison Grinthal and Sunny, Steffi and Aizenberg, Michael and Aizenberg, Joanna} } @article {1223554, title = {Research Update: Liquid gated membrane filtration performance with inorganic particle suspensions}, journal = {APL MaterialsAPL Materials}, volume = {6}, year = {2018}, note = {doi: 10.1063/1.5047480}, month = {2018}, pages = {100703}, publisher = {American Institute of Physics}, url = {https://doi.org/10.1063/1.5047480}, author = {Jack Alvarenga and Ainge,Yuki and Williams,Chris and Maltz,Aubrey and Blough,Thomas and Khan,Mughees and Aizenberg, Joanna} } @article {1223552, title = {Multiresponsive polymeric microstructures with encoded predetermined and self-regulated deformability}, journal = {Proceedings of the National Academy of Sciences}, volume = {115}, year = {2018}, month = {2018/12/18}, pages = {12950}, abstract = {The range of allowed deformation modes currently described for the actuation of microstructures is limited. In this work we introduce magnetic-field{\textendash}guided encoding of highly controlled molecular anisotropy into 3D liquid-crystalline elastomer microstructures capable of displaying unique multiresponsive, shape-changing behaviors. The richness of the predetermined and self-regulated deformations and region-specific motions in these microstructural arrays gives rise to physicochemical insights, as well as potential applications in controlled adhesion, information encryption, soft robotics, and self-regulated light{\textendash}material interactions.Dynamic functions of biological organisms often rely on arrays of actively deformable microstructures undergoing a nearly unlimited repertoire of predetermined and self-regulated reconfigurations and motions, most of which are difficult or not yet possible to achieve in synthetic systems. Here, we introduce stimuli-responsive microstructures based on liquid-crystalline elastomers (LCEs) that display a broad range of hierarchical, even mechanically unfavored deformation behaviors. By polymerizing molded prepolymer in patterned magnetic fields, we encode any desired uniform mesogen orientation into the resulting LCE microstructures, which is then read out upon heating above the nematic{\textendash}isotropic transition temperature (TN{\textendash}I) as a specific prescribed deformation, such as twisting, in- and out-of-plane tilting, stretching, or contraction. By further introducing light-responsive moieties, we demonstrate unique multifunctionality of the LCEs capable of three actuation modes: self-regulated bending toward the light source at T \&lt; TN{\textendash}I, magnetic-field{\textendash}encoded predetermined deformation at T \&gt; TN{\textendash}I, and direction-dependent self-regulated motion toward the light at T \&gt; TN{\textendash}I. We develop approaches to create patterned arrays of microstructures with encoded multiple area-specific deformation modes and show their functions in responsive release of cargo, image concealment, and light-controlled reflectivity. We foresee that this platform can be widely applied in switchable adhesion, information encryption, autonomous antennae, energy harvesting, soft robotics, and smart buildings.}, url = {http://www.pnas.org/content/115/51/12950.abstract}, author = {Yuxing Yao and Waters, James T. and Anna V. Shneidman and Cui, Jiaxi and Wang, Xiaoguang and Mandsberg, Nikolaj K. and Li, Shucong and Balazs, Anna C. and Aizenberg, Joanna} } @article {1167791, title = {Multi-responsive polymeric microstructures with encoded pre-determined and self-regulated deformability}, journal = {Proceedings of the National Academy of Sciences}, volume = {115}, year = {2018}, pages = {12950-12955}, url = {https://www.pnas.org/content/115/51/12950.abstract}, author = {Yao, Y. and Waters, J. and Shneidman, A.V. and Cui, J. and X Wang and Mandsberg, N. K. and Li, S. and Balazs, A.C. and Aizenberg, Joanna} } @article {1145454, title = {Probing atomic distributions in mono- and bimetallic nanoparticles by supervised machine learning}, journal = {Nano Letters}, year = {2018}, author = {Janis Timoshenko and Cody Wrasman and Luneau, Mathilde and Shirman, Tanya and Matteo Cargnello and Simon Bare and Aizenberg, Joanna and Cynthia Friend and Anatoly Frenkel} } @article {1142248, title = {Film Dynamics and Lubricant Depletion by Droplets Moving on Lubricated Surfaces}, journal = {PHYSICAL REVIEW}, volume = {8}, year = {2018}, abstract = {

Lubricated surfaces have shown promise in numerous applications where impinging foreign droplets
must be removed easily; however, before they can be widely adopted, the problem of lubricant depletion,
which eventually leads to decreased performance, must be solved. Despite recent progress, a quantitative
mechanistic explanation for lubricant depletion is still lacking. Here, we first explain the shape of a droplet
on a lubricated surface by balancing the Laplace pressures across interfaces. We then show that the
lubricant film thicknesses beneath, behind, and wrapping around a moving droplet change dynamically

with the droplet{\textquoteright}s speed{\textemdash}analogous to the classical Landau-Levich-Derjaguin problem. The intercon-
nected lubricant dynamics results in the growth of the wetting ridge around the droplet, which is the

dominant source of lubricant depletion. We then develop an analytic expression for the maximum amount
of lubricant that can be depleted by a single droplet. Counterintuitively, faster-moving droplets subjected to
higher driving forces deplete less lubricant than their slower-moving counterparts. The insights developed
in this work will inform future work and the design of longer-lasting lubricated surfaces.

}, author = {Michael J. Kreder and Dan Daniel and Adam Tetreault and Zhenle Cao and Baptiste Lemaire and Jaakko V.I. Timonen and Aizenberg, Joanna} } @article {1127117, title = {Origins of liquid-repellency on structured, flat, and lubricated surfaces }, journal = {Phys. Rev. Lett.}, year = {2018}, note = {

The work was supported by the Office of Naval Research, U.S. Department of Defense, under MURI Award No. N00014-12-1-0875.

}, abstract = {There are currently three main classes of liquid-repellent surfaces: micro-/nano-structured superhydrophobic surfaces, flat surfaces grafted with {\textquoteleft}liquid-like{\textquoteright} polymer brushes, and lubricated surfaces. Despite recent progress, the mechanistic explanation for the differences in droplet behavior on such surfaces is still under debate. Here, we measured the dissipative force acting on a droplet moving on representatives of these surfaces at different velocities\ U\ = 0.01--1 mm/s using a cantilever force sensor with sub-μN accuracy, and correlated it to the contact line dynamics observed using optical interferometry at high spatial (micron) and temporal (lessthan\ 0.1s) resolutions. We find that the dissipative force---due to very different physical mechanisms at the contact line---is independent of velocity on superhydrophobic surfaces, but depends non-linearly on velocity for flat and lubricated surfaces. The techniques and insights presented here will inform future work on liquid-repellent surfaces and enable their rational design.}, author = {Dan Daniel and Jaakko V.I. Timonen and Ruoping Li and Seneca J. Velling and Michael J. Kreder and Adam Tetreault and Aizenberg, Joanna} } @article {1123694, title = {Pneumatically adaptive light modulation system (PALMS) for buildings}, journal = {Materials \& Design}, volume = {152}, year = {2018}, pages = {156-167}, abstract = {

This research introduces a novel approach to control light transmittance based on flexible polydimethylsiloxane (PDMS) films that have been plasma-treated such that micro-scale surface features have a visual effect as the film responds to applied strain. The effect is continuously tunable from optically clear (71.5\% Transmittance over a 400{\textendash}900 nm wavelength) to completely diffuse (18.1\% T). Changes in the film{\textquoteright}s optical properties are triggered by bi-axial strains applied using a pneumatic system to form pressurized envelopes. This paper reports on a series of experimental studies and provides system integration research using prototypes, simulations and geometric models to correlate measured optical properties, strain, and global surface curvatures. In conclusion, a design is proposed to integrate PDMS light control within existing building envelopes.

Two alternatives are investigated and compared: System A uses positive pressure featuring an exterior grid to restrain and shape the inflated film during expansion; System B uses negative pressure where the films are shaped according to the geometry of an interstitial grid that serves as a spacer between two film surfaces. Both systems can provide effective control of opacity levels using pneumatic pressure and may be suitable for use with existing glazing systems or ethylene tetrafluoroethylene (ETFE) pneumatic envelopes.

}, url = {https://www.sciencedirect.com/science/article/pii/S0264127518303149}, author = {K. Hinz and J. Alvarenga and Kim, P. and D. Park and Aizenberg, J. and M. Bechthold} } @article {1121350, title = {Dropwise Condensation on Hydrophobic Bumps and Dimples}, journal = {Appl. Phys. Lett.}, volume = {112}, year = {2018}, note = {This work was partially supported by the Water Collaboration Seed Funds program of the Northwestern Center for Water Research.}, pages = {151605}, abstract = {Surface topography plays an important role in promoting or suppressing localized condensation. In this work, we study the growth of water droplets on hydrophobic convex surface textures such as bumps and concave surface textures such as dimples with a millimeter scale radius of curvature. We analyze the spatio-temporal droplet size distribution under a supersaturation condition created by keeping the uniform surface temperature below the dew point and show its relationship with the sign and magnitude of the surface curvature. In particular, in contrast to the well-known capillary condensation effect, we report an unexpectedly less favorable condensation on smaller, millimeter-scale dimples where the capillary condensation effect is negligible. To explain these experimental results, we numerically calculated the diffusion flux of water vapor around the surface textures, showing that its magnitude is higher on bumps and lower on dimples compared to a flat surface. We envision that our understanding of millimetric surface topography can be applied to improve the energy efficiency of condensation in applications such as water harvesting, heating, ventilation, and air conditioning systems for buildings and transportation, heat exchangers, thermal desalination plants, and fuel processing systems.}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:36642002}, author = {Yuehan Yao and Aizenberg, Joanna and Kyoo-Chul Park} } @article {1119577, title = {Directed nucleation and growth by balancing local supersaturation and substrate/nucleus lattice mismatch}, journal = {PNAS}, volume = {14}, year = {2018}, note = {Dr. Liesbeth Janssen and Prof. Pieter Rein ter Wolde are kindly acknowledged for help with the manuscript. This research was supported by the NSF Designing Materials to Revolutionize and Engineer\ our Future under Award 15-33985 and the Harvard Materials Research Science and Engineering Centers under Award DMR 14-20570. W.L.N. thanks the Netherlands Organization for Scientific Research (NWO) for financial support from a VENI grant. L.L. thanks the Department of Mechanical Engineering at Virginia Polytechnic Institute and State University for support. Electron microscopy and FIB milling was performed at the Center for Nanoscale Systems at Harvard University, supported by the NSF under Award ECS-0335765, and at the Amsterdam nanoCenter, which was financially supported by NWO.}, pages = {3573-3580}, abstract = {Controlling nucleation and growth is crucial in biological and artificial mineralization and self-assembly processes. The nucleation barrier is determined by the chemistry of the interfaces at which crystallization occurs and local supersaturation. Although chemically tailored substrates and lattice mismatches are routinely used to modify energy landscape at the substrate/nucleus interface and thereby steer heterogeneous nucleation, strategies to combine this with control over local supersaturations have remained virtually unexplored. Here we demonstrate simultaneous control over both parameters to direct the positioning and growth direction of mineralizing compounds on preselected polymorphic substrates. We exploit the polymorphic nature of calcium carbonate (CaCO3) to locally manipulate the carbonate concentration and lattice mismatch between the nucleus and substrate, such that barium carbonate (BaCO3) and strontium carbonate (SrCO3) nucleate only on specific CaCO3 polymorphs. Based on this approach we position different materials and shapes on predetermined CaCO3 polymorphs in sequential steps, and guide the growth direction using locally created supersaturations. These results shed light on nature{\textquoteright}s remarkable mineralization capabilities and outline fabrication strategies for advanced materials, such as ceramics, photonic structures, and semiconductors.}, url = {http://www.pnas.org/content/early/2018/03/15/1712911115}, author = {Li, L. and A. J. Fijneman and J. A. Kaandorp and Aizenberg, J. and W.L. Noorduin} } @article {1116295, title = {Dynamic air/liquid pockets for guiding microscale flow}, journal = {Nat. Commun.}, volume = {9}, year = {2018}, note = {

This work was supported by the US Department of Energy under Award Number DE-SC0005247 and by National Natural Science Foundation of China (Grant No. 21673197). X.H. acknowledges the support from the Young Overseas High-level Talents Introduction Plan, the 111 Project (Grant No. B16029), and NFFTBS (Grant No. J1310024). J.Y.L. acknowledges the support of Wyss Technology Development Fellowship from the Wyss Institute for Biologically Inspired Engineering at Harvard University. The authors thank G.M. Whitesides, J. Weaver, M. Khan, R.T. Blough, T.S. Wong, B.D. Hatton, Q.H. Liu, and F. Wu for discussion and help.

}, pages = {733}, abstract = {

Microscale flows of fluids are mainly guided either by solid matrices or by liquid{\textendash}liquid interfaces. However, the solid matrices are plagued with persistent fouling problems, while liquid{\textendash}liquid interfaces are limited to low-pressure applications. Here we report a dynamic liquid/solid/gas material containing both air and liquid pockets, which are formed by partially infiltrating a porous matrix with a functional liquid. Using detailed theoretical and experimental data, we show that the distribution of the air- and liquid-filled pores is responsive to pressure and enables the formation and instantaneous recovery of stable liquid{\textendash}liquid interfaces that sustain a wide range of pressures and prevent channel contamination. This adaptive design is demonstrated for polymeric materials and extended to metal-based systems that can achieve unmatched mechanical and thermal stability. Our platform with its unique adaptive pressure and antifouling capabilities may offer potential solutions to flow control in microfluidics, medical devices, microscale synthesis, and biological assays.

}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:35015070}, author = {Xu Hou and Jianyu Li and Alexander B. Tesler and Yuxing Yao and Miao Wang and Lingli Min and Zhizhi Sheng and Aizenberg, Joanna} } @article {1112958, title = {Nanocrystalline Precursors for the Co-Assembly of Crack-Free Metal Oxide Inverse Opals}, journal = {Adv. Mater.}, volume = {30}, year = {2018}, note = {

K.R.P. and T.S. contributed equally to this work. The authors acknowledge Dr. Alison Grinthal and Dr. Michael Aizenberg for thoughtful discussions and assistance with the manuscript. K.R.P. acknowledges support from a graduate fellowship from the Department of Defense. T.S. acknowledges support from the Weizmann Institute of Science-National Postdoctoral Award Program for Advancing Women in Science. The materials design aspects of this work are supported by the National Science Foundation (NSF) Designing Materials to Revolutionize and Engineer our Future program under Award No. DMR 1533985. Electron microscopy and other characterizations were performed in part at the Harvard University Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Coordinated Infrastructure Network (NNCI), which is supported by the National Science Foundation under NSF ECCS Award No. 1541959.

}, pages = {1706329}, abstract = {

Inorganic microstructured materials are ubiquitous in nature. However, their formation in artificial self-assembly systems is challenging as it involves a complex interplay of competing forces during and after assembly. For example, colloidal assembly requires fine-tuning of factors such as the size and surface charge of the particles and electrolyte strength of the solvent to enable successful self-assembly and minimize crack formation. Co-assembly of templating colloidal particles together with a sol{\textendash}gel matrix precursor material helps to release stresses that accumulate during drying and solidification, as previously shown for the formation of high-quality inverse opal (IO) films out of amorphous silica. Expanding this methodology to crystalline materials would result in microscale architectures with enhanced photonic, electronic, and catalytic properties. This work describes tailoring the crystallinity of metal oxide precursors that enable the formation of highly ordered, large-area (mm2) crack-free titania, zirconia, and alumina IO films. The same bioinspired approach can be applied to other crystalline materials as well as structures beyond IOs.

}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201706329}, author = {Katherine R. Phillips and Shirman, Tanya and Shirman, Elijah and Anna V. Shneidman and Theresa M. Kay and Aizenberg, Joanna} } @article {1112425, title = {Bioinspired Universal Flexible Elastomer-Based Microchannels}, journal = {Small}, volume = {14}, year = {2018}, note = {

F.W., S.C., and B.C. contributed equally to this work. This work was supported by the National Natural Science Foundation of China (No. 21673197), Young Overseas High-level Talents Introduction Plan, the 111 Project (No. B16029), and the Fundamental Research Funds for the Central Universities of China (No. 20720170050). J.A. acknowledges the Department of Energy under Award No. DE-SC0005247 and the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award No. DE-AR0000326. Y.S.Z. acknowledges the National Cancer Institute of the National Institutes of Health Pathway to Independence Award (K99CA201603), the Lush Prize, and the Science and Technology Commission of Shanghai Municipality (STCSM) 17JC 1400200. The authors thank M. Eggersdorfer, H. Meng, and Y. Fan for discussion and help.

}, pages = {1702170}, abstract = {

Flexible and stretchable microscale fluidic devices have a broad range of potential applications, ranging from electronic wearable devices for convenient digital lifestyle to biomedical devices. However, simple ways to achieve stable flexible and stretchable fluidic microchannels with dynamic liquid transport have been challenging because every application for elastomeric microchannels is restricted by their complex fabrication process and limited material selection. Here, a universal strategy for building microfluidic devices that possess exceptionally stable and stretching properties is shown. The devices exhibit superior mechanical deformability, including high strain (967\%) and recovery ability, where applications as both strain sensor and pressure-flow regulating device are demonstrated. Various microchannels are combined with organic, inorganic, and metallic materials as stable composite microfluidics. Furthermore, with surface chemical modification these stretchable microfluidic devices can also obtain antifouling property to suit for a broad range of industrial and biomedical applications.

}, url = {https://onlinelibrary.wiley.com/doi/full/10.1002/smll.201702170}, author = {Feng Wu and Songyue Chen and Baiyi Chen and Miao Wang and Lingli Min and Jack Alvarenga and Jie Ju and Ali Khademhosseini and Yuxing Yao and Yu Shrike Zhang and Aizenberg, Joanna and Xu Hou} } @article {1112411, title = {Stable Liquid Jets Bouncing off Soft Gels}, journal = {Phys. Rev. Lett.}, volume = {120}, year = {2018}, note = {

We would like to thank Prof. Michael Brenner, Prof. L. Mahadevan, and Prof. Kyoo-Chul Park for useful discussions. The work was supported partially by the ONR MURI Grant No. N00014-12-1-0875 (fluid dynamics studies) and the U.S. Department of Energy Award No. DE-SC0005247 (materials synthesis). We acknowledge support from the Harvard Materials Research Science and Engineering Center (MRSEC) through Grant No. DMR-1420570.

}, pages = {028006}, abstract = {

A liquid jet can stably bounce off a sufficiently soft gel by following the contour of the dimple created upon impact. This new phenomenon is insensitive to the wetting properties of the gels and was observed for different liquids over a wide range of surface tensions, γ =\ 24 - 72 mN/m. In contrast, other jet rebound phenomena are typically sensitive to γ: only a high γ jet rebounds off a hard solid (e.g. superhydrophobic surface) and only a low γ jet bounces off a liquid bath. This is because an air layer must be stabilized between the two interfaces. For a soft gel, no air layer is necessary and the jet rebound remains stable even when there is direct liquid-gel contact.

}, url = {https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.120.028006}, author = {Dan Daniel and Xi Yao and Aizenberg, Joanna} } @article {1096491, title = {Emerging Optical Properties from the Combination of Simple Optical Effects}, journal = {Rep. Prog. Phys.}, volume = {81}, year = {2018}, note = {This work was supported by the NSF Designing Materials to Revolutionize and Engineer our Future program (DMR 1533985).}, pages = {016402}, abstract = {

Structural color arises from the patterning of geometric features or refractive indices of the constituent materials on the length-scale of visible light. Many different organisms have developed structurally colored materials as a means of creating multifunctional structures or displaying colors for which pigments are unavailable. By studying such organisms, scientists have developed artificial structurally colored materials that take advantage of the hierarchical geometries, frequently employed for structural coloration in nature. These geometries can be combined with absorbers{\textemdash}a strategy also found in many natural organisms{\textemdash}to reduce the effects of fabrication imperfections. Furthermore, artificial structures can incorporate materials that are not available to nature{\textemdash}in the form of plasmonic nanoparticles or metal layers{\textemdash}leading to a host of novel color effects. Here, we explore recent research involving the combination of different geometries and materials to enhance the structural color effect or to create entirely new effects, which cannot be observed otherwise.

}, url = {http://iopscience.iop.org/article/10.1088/1361-6633/aa8372/meta}, author = {England, G.T. and Aizenberg, J.} } @article {1066606, title = {New Architectures for Designed Catalysts: Selective Oxidation using AgAu Nanoparticles on Colloid-Templated Silica}, journal = {Chem. Eur. J.}, volume = {24}, year = {2018}, note = {This work was supported as part of the Integrated Mesoscale Architectures for Sustainable Catalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under award $\#$DE-SC0012573. T.S. acknowledges support from the Weizmann Institute of Science{\textemdash}National Postdoctoral Award Program for Advancing Women in Science. This work was performed in part at the Harvard University Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Coordinated Infrastructure Network (NNCI), which is supported by the National Science Foundation under NSF ECCS award no. 1541959.}, pages = {1833 {\textendash}1837 }, abstract = {

A highly modular synthesis of designed catalysts with controlled bimetallic nanoparticle size and composition and a well-defined structural hierarchy is demonstrated. Exemplary catalysts{\textemdash}bimetallic dilute Ag-in-Au nanoparticles partially embedded in a porous SiO2 matrix (SiO2{\textendash}AgxAuy){\textemdash} were synthesized by the decoration of polymeric colloids with the bimetallic nanoparticles followed by assembly into a colloidal crystal backfilled with the matrix precursor and subsequent removal of the polymeric template. This work reports that these new catalyst architectures are significantly better than nanoporous dilute AgAu alloy catalysts (nanoporous Ag3Au97) while retaining a clear predictive relationship between their surface reactivity with that of single-crystal Au surfaces. This paves the way for broadening the range of new catalyst architectures required for translating the designed principles developed under controlled conditions to designed catalysts under operating conditions for highly selective coupling of alcohols to form esters. Excellent catalytic performance of the porous SiO2{\textendash}AgxAuy structure for selective oxidation of both methanol and ethanol to produce esters with high conversion efficiency, selectivity, and stability was demonstrated, illustrating the ability to translate design principles developed for support-free materials to the colloid-templated structures. The synthetic methodology reported is customizable for the design of a wide range of robust catalytic systems inspired by design principles derived from model studies. Fine control over the composition, morphology, size, distribution, and availability of the supported nanoparticles was demonstrated.

}, url = {http://onlinelibrary.wiley.com/doi/10.1002/chem.201704552/full}, author = {Shirman, Tanya and Lattimer, Judith and Luneau, Mathilde and Shirman, Elijah and Reece, Christian and Aizenberg, Michael and Madix, Robert J. and Aizenberg, Joanna and Friend, Cynthia M.} } @article {1097706, title = {Modular Design of Advanced Catalytic Materials Using Hybrid Organic{\textendash}Inorganic Raspberry Particles}, journal = {Adv. Func. Mater.}, year = {2017}, note = {

E.S., T.S., A.V.S., and A.G. contributed equally to this work. The authors acknowledge David and Elisha Shirman for thoughtful discussions and their assistance with the manuscript. This work was partially supported by the Integrated Mesoscale Architectures for Sustainable Catalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under award $\#$DE-SC0012573. This work was performed in part at the Harvard University Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Coordinated Infrastructure Network (NNCI), which is supported by the National Science Foundation under NSF ECCS award no. 1541959.

}, pages = {1704559}, abstract = {

Catalysis is one of the most sophisticated areas of materials research that encompasses a diverse set of materials and phenomena occurring on multiple length and time scales. Designing catalysts that can be broadly applied toward global energy and environmental challenges requires the development of universal frameworks for complex catalytic systems through rational and independent (or quasi-independent) optimization of multiple structural and compositional features. Toward addressing this goal, a modular platform is presented in which sacrificial organic colloids bearing catalytic nanoparticles on their surfaces self-assemble with matrix precursors, simultaneously structuring the resulting porous networks and fine-tuning the locations of catalyst particles. This strategy allows combinatorial variations of the material building blocks and their organization, in turn providing numerous degrees of freedom for optimizing the material{\textquoteright}s functional properties, from the nanoscale to the macroscale. The platform enables systematic studies and rational design of efficient and robust systems for a wide range of catalytic and photocatalytic reactions, as well as their integration into industrial and other real-life environments.

}, url = {https://onlinelibrary.wiley.com/doi/full/10.1002/adfm.201704559}, author = {Shirman, Elijah and Shirman, Tanya and Anna V. Shneidman and Alison Grinthal and Katherine R. Phillips and Hayley Whelan and Eli Bulger and Marcus Abramovitch and Jatin Patil and Rochelle Nevarez and Aizenberg, Joanna} } @article {1078226, title = {Inverting the Swelling Trends in Modular Self-Oscillating Gels Crosslinked by Redox-Active Metal Bipyridine Complexes}, journal = {Adv. Func. Mater.}, year = {2017}, note = {The work was supported by the DOE under Award DE-SC0005247. K.O. is thankful for JSPS Research Fellowship and JSPS Postdoctoral Fellowship for Research Abroad. The authors thank Dr. Sunia A. Trauger (Harvard FAS Center for Systems Biology, Small Molecule Mass Spectrometry) for HRMS data of metal complexes, Dr. Shao-Liang Zheng (Harvard Department of Chemistry and Chemical Biology, X-Ray Laboratory) for his help with the X-ray data collection and structure determination, Chris Johnson, and Jack Alvarenga for technical assistance.}, pages = {1704205}, abstract = {

The developing field of active, stimuli-responsive materials is in need for new dynamic architectures that may offer unprecedented chemomechanical switching mechanisms. Toward this goal, syntheses of polymerizable bipyridine ligands, bis(4-vinylbenzyl)[2,2'-bipyridine]-4,4'-dicarboxylate and N4,N4'-bis(4-vinylphenyl)-2,2'-bipyridine-4,4'-dicarboxamide, and a number of redox-active Ruthenium(II) and Iron(II) complexes with them are reported. Detailed characterizations by NMR, Fourier transform infrared spectroscopy, high-resolution mass-spectrometry, X-ray, and cyclic voltammetry show that the topology of these molecules allows them to serve as both comonomers and crosslinkers in polymerization reactions. Electronic properties of the ligands are tunable by choosing carboxylate- or carboxamido-linkages between the core and the vinylaryl moieties, leading to a library of Ru and Fe complexes with the M(III)/M(II) standard redox potentials suitable for catalyzing self-oscillating Belousov{\textendash}Zhabotinskii (BZ) reaction. New poly(N-isopropylacrylamide)-based redox-responsive functional gels containing hydrophilic comonomers, which have been prepared using representative Ru bpy complexes as both a crosslinker and redox-active catalyst, exhibit a unique feature: their swelling/contraction mode switches its dependence on the oxidation state of the Ru center, upon changing the ratio of comonomers in the hybrid gel network. The BZ self-oscillations of such crosslinked hydrogels have been observed and quantified for both supported film and free-standing gel samples, demonstrating their potential as chemomechanically active modules for new functional materials.

}, url = {http://onlinelibrary.wiley.com/doi/10.1002/adfm.201704205/abstract}, author = {Aizenberg, Michael and Okeyoshi, Kosuke and Aizenberg, Joanna} } @article {1071426, title = {A Biologically Inspired, Functionally Graded End Effector for Soft Robotics Applications}, journal = {Soft Robotics}, volume = {4}, year = {2017}, note = {This work was supported by funding from the Wyss Institute for Biologically Inspired Engineering and by the Materials Research Science and Engineering Center under the National Science Foundation Award (Grant No. DMR- 1420570). K.B. and J.A. also acknowledge support from the National Science Foundation (Grant No. DMR-1533985). C.C. also acknowledges support from the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1144086.}, pages = {317-323}, abstract = {

Soft robotic actuators offer many advantages over their rigid counterparts, but they often are unable to apply highly localized point loads. In contrast, many invertebrates have not only evolved extremely strong {\textquoteleft}{\textquoteleft}hybrid appendages{\textquoteright}{\textquoteright} that are composed of rigid ends that can grasp, puncture, and anchor into solid substrates, but they also are compliant and resilient, owing to the functionally graded architecture that integrates rigid termini with their flexible and highly extensible soft musculatures. Inspired by the design principles of these natural hybrid appendages, we demonstrate a synthetic hybrid end effector for soft-bodied robots that exhibits excellent piercing abilities. Through the incorporation of functionally graded interfaces, this design strategy minimizes stress concentrations at the junctions adjoining the fully rigid and soft components and optimizes the bending stiffness to effectively penetrate objects without interfacial failure under shear and compressive loading re- gimes. In this composite architecture, the radially aligned tooth-like elements apply balanced loads to maximize puncturing ability, resulting in the coordinated fracture of an object of interest.

}, url = {https://www.liebertpub.com/doi/abs/10.1089/soro.2017.0002}, author = {Kumar, Kitty and Liu, Jia and Christianson, Caleb and Ali, Mustafa and Tolley, Michael T. and Aizenberg, Joanna and Ingber, Donald E. and Weaver, James C. and Bertoldi, Katia} } @article {1042391, title = {Preventing mussel adhesion using lubricant-infused materials}, journal = {Science}, volume = {357}, year = {2017}, note = {

This study was funded by the Singapore Maritime Institute (SMI), grant SMI-2013-MA-03 (A.M.). This work was also funded by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under award DE-AR0000326, and by the Office of Naval Research (ONR), U.S. Department of Defense, under award N00014-16-1-3169. N.V. acknowledges funding of the Deutsche Forschungsgemeinschaft (DFG) through the Cluster of Excellence Engineering of Advanced Materials (EXC 315) and the Interdisciplinary Center for Functional Particle Systems (FPS). We thank A. Tesler for providing i-WO samples, D. Daniel for discussion on interfacial energies, E. Maldonado for help with the field study, and Stellwagen Bank National Marine Sanctuary for providing the field site and field site support. The transcriptome of P. viridis foot used to identify TRP channels is available at https://www.ncbi.nlm.nih.gov/nuccore/GEKL00000000. S.S., N.V., and J.A. are inventors on a patent application (US20150210951A1) submitted by Harvard University that covers LBL slippery liquid- infused porous surfaces (SLIPS). J.A. is an inventor on a U.S. Patent Application ($\#$ 14/414,291) submitted by Harvard University that\ overs 3D SLIPS. J.A. is the founder of the start-up company SLIPS Technologies, Inc.

}, pages = {668-673}, abstract = {

Mussels are opportunistic macrofouling organisms that can attach to most immersed solid surfaces, leading to serious economic and ecological consequences for the maritime and aquaculture industries. We demonstrate that lubricant-infused coatings exhibit very low preferential mussel attachment and ultralow adhesive strengths under both controlled laboratory conditions and in marine field studies. Detailed investigations across multiple length scales{\textemdash}from the molecular-scale characterization of deposited adhesive proteins to nanoscale contact mechanics to macroscale live observations{\textemdash}suggest that lubricant infusion considerably reduces fouling by deceiving the mechanosensing ability of mussels, deterring secretion of adhesive threads, and decreasing the molecular work of adhesion. Our study demonstrates that lubricant infusion represents an effective strategy to mitigate marine biofouling and provides insights into the physical mechanisms underlying adhesion prevention.

}, url = {http://science.sciencemag.org/cgi/content/full/357/6352/668?ijkey=uFJi2l9MM5Mxs\&keytype=ref\&siteid=sci}, author = {Amini, S. and Kolle, S. and Petrone, L. and Ahanotu, O. and Sunny, S. and Sutanto, C.N. and Hoon, S. and Cohen, L. and J. C. Weaver and Aizenberg, J. and Vogel, N. and A. Miserez} } @article {1025896, title = {Oleoplaning droplets on lubricated surfaces}, journal = {Nat. Phys.}, volume = {13}, year = {2017}, note = {

We thank K.-C. Park, C. N. Kaplan and H. A. Stone for fruitful discussions. The work was supported by the Office of Naval Research, US Department of Defense, under MURI Award No. N00014-12-1-0875. J.V.I.T. was supported by the European Commission through the Seventh Framework Programme (FP7) project DynaSLIPS (project number 626954). We acknowledge the use of the facilities at the Harvard Center for Nanoscale Systems supported by the NSF under Award No. ECS-0335765 and at the Harvard Materials Research Science and Engineering Center (MRSEC) under Award No. DMR-1420570.

}, pages = {1020-1025}, abstract = {

Recently, there has been much interest in using lubricated surfaces to achieve extreme liquid repellency: a foreign droplet immiscible with the underlying lubricant layer was shown to slide o at a small tilt angle \<5{\textopenbullet} . This behaviour was hypothesized to arise from a thin lubricant overlayer film sandwiched between the droplet and solid substrate, but this has not been observed experimentally. Here, using thin-film interference, we are able to visualize the intercalated film under both static and dynamic conditions. We further demonstrate that for a moving droplet, the film thickness follows the Landau{\textendash}Levich{\textendash}Derjaguin law. The droplet is therefore oleoplaning{\textemdash}akin to tyres hydroplaning on a wet road{\textemdash}with minimal dissipative force and no contact line pinning. The techniques and insights presented in this study will inform future work on the fundamentals of wetting for lubricated surfaces and enable their rational design.

}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:34609602}, author = {Dan Daniel and Jaakko V.I. Timonen and Ruoping Li and Seneca J. Velling and Aizenberg, Joanna} } @article {1011521, title = {The Optical Janus Effect: Asymmetric Structural Color Reflection Materials}, journal = {Adv. Mater.}, volume = {29}, year = {2017}, note = {

The work was supported by the National Science Foundation (NSF) under the Award No. DMREF-1533985. Fabrication was carried out at the Harvard Center for Nanoscale Systems, which is supported by the NSF{\textquoteright}s Materials Research Science and Engineering Centers Program DMR- 1420570. N.V. acknowledges the support of the Cluster of Excellence Engineering of Advanced Materials (EAM) and of the Interdisciplinary Center for Functional Particle Systems (FPS) at Friedrich-Alexander University Erlangen-Nürnberg. The authors would like to thank Orad Reshef, Alexander Tesler, Alison Grinthal, Anna Shneidman, and Peter Korevaar for helpful discussions. G.T.E., N.V., and J.A. designed research. C.R. and E.S. synthesized nanoparticles. G.T.E., C.R., T.K., and E.S. fabricated samples. G.T.E. and C.R. measured samples. G.T.E. performed calculations. G.E., N.V., and J.A. wrote the manuscript. All the authors discussed and reviewed the manuscript.

}, pages = {1606876}, abstract = {Structurally colored materials are often used for their resistance to photobleaching and their complex viewing-direction-dependent optical properties. Frequently, absorption has been added to these types of materials in order to improve the color saturation by mitigating the effects of nonspecific scattering that is present in most samples due to imperfect manufacturing procedures. The combination of absorbing elements and structural coloration often yields emergent optical properties. Here, a new hybrid architecture is introduced that leads to an interesting, highly directional optical effect. By localizing absorption in a thin layer within a transparent, structurally colored multilayer material, an optical Janus effect is created, wherein the observed reflected color is different on one side of the sample than on the other. A systematic characterization of the optical properties of these structures as a function of their geometry and composition is performed. The experimental studies are coupled with a theoretical analysis that enables a precise, rational design of various optical Janus structures with highly controlled color, pattern, and fabrication approaches. These asymmetrically colored materials will open applications in art, architecture, semitransparent solar cells, and security features in anticounterfeiting materials.}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201606876}, author = {England, GT and Russell, C and Shirman, E and Kay, T and Vogel, N and Aizenberg, J} } @article {1007206, title = {Emerging Trends in Micro- and Nanoscale Technologies in Medicine: From Basic Discoveries to Translation}, journal = {ACS Nano}, volume = {11}, year = {2017}, note = {

The idea and outline of this contribution was derived from the exchange of ideas among authors in the context of the Third Annual Workshop on Microtechnologies and Nanotechnologies for Medicine. This workshop was organized by the Biomaterials Innovation Research Center (BIRC) at Harvard-MIT Health Sciences and Technologies and was partially sponsored by the Tec de Monterrey and MIT Nanotechnology Program, the MIT International Science and Technology Initiatives (MISTI), and the Department of Chemical Engineering at Northeastern University.

}, pages = {5195-5214}, abstract = {

We discuss the state of the art and innovative micro- and nanoscale technologies that are finding niches and opening up new opportunities in medicine, particularly in diagnostic and therapeutic applications. We take the design of point-of-care applications and the capture of circulating tumor cells as illustrative examples of the integration of micro- and nanotechnologies into solutions of diagnostic challenges. We describe several novel nanotechnologies that enable imaging cellular structures and molecular events. In therapeutics, we describe the utilization of micro- and nanotechnologies in applications including drug delivery, tissue engineering, and pharmaceutical development/testing. In addition, we discuss relevant challenges that micro- and nanotechnologies face in achieving cost-effective and widespread clinical implementation as well as forecasted applications of micro- and nanotechnologies in medicine.

}, url = {https://pubs.acs.org/doi/abs/10.1021/acsnano.7b01493}, author = {Alvarez, MM and Aizenberg, J and Analoui, M and Andrews, AM and Bisker, G and Boyden, ES and Kamm, RD and Karp, JM and Mooney, DJ and Oklu, R and Peer, D and Stolzoff, M and Strano, MS and Trujillo-de Santiago, G and Webster, TJ and Weiss, PS and Khademhosseini, A} } @article {996181, title = {Interplay between materials and microfluidics}, journal = {Nat. Rev. Mater.}, volume = {2}, year = {2017}, note = {

The authors acknowledge funding from the US National Institutes of Health (AR057837, DE021468, D005865, AR068258, AR066193, EB022403, EB021148), the Air Force Office of Scientific Research Award (USA, FA9550-15-1-0273), the Presidential Early Career Award for Scientists and Engineers (USA), Consejo Nacional de Ciencia y Tecnología (Mexico, scholarships 262130 and 234713), Tecnológico de Monterrey (Mexico), Massachusetts Institute of Technology (MIT) International Science and Technology Initiatives and Fundación México en Harvard. This research has been partially funded by the Tecnológico de Monterrey and MIT Nanotechnology Program. X.H. acknowledges the support of the Recruitment Program for Young Professionals (China), the National Natural Science Foundation (China, 21673197), and the Research Institute for Biomimetics and Soft Matter, Fujian Provincial Key Laboratory for Soft Functional Materials Research, Xiamen University (China), supported by the 111 Project (B16029). Y.S.Z. acknowledges the National Cancer Institute of the US National Institutes of Health Pathway to Independence Award (K99CA201603). J.R. acknowledges sup- port from the Portuguese Foundation for Science and Technology (SFRH/BD/51679/2011). P.S.W., A.M.A. and J.A. acknowledge support from the Kavli Foundation (USA). A.M.A. acknowledges support from the Hatos Center for Neuropharmacology (USA). S.J.J. acknowledges the support of the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at the University of California Los Angeles (UCLA) Training Program through its Clinical Fellowship Training Award Program, as well as the UCLA Children{\textquoteright}s Discovery and Innovation Institute{\textquoteright}s Fellows Research Support Award.

}, pages = {17016}, abstract = {

Developments in the field of microfluidics have triggered technological revolutions in many disciplines, including chemical synthesis, electronics, diagnostics, single-cell analysis, micro- and nanofabrication, and pharmaceutics. In many of these areas, rapid growth is driven by the increasing synergy between fundamental materials development and new microfluidic capabilities. In this Review, we critically evaluate both how recent advances in materials fabrication have expanded the frontiers of microfluidic platforms and how the improved microfluidic capabilities are, in turn, furthering materials design. We discuss how various inorganic and organic materials enable the fabrication of systems with advanced mechanical, optical, chemical, electrical and biointerfacial properties {\textemdash} in particular, when these materials are combined into new hybrids and modular configurations. The increasing sophistication of microfluidic techniques has also expanded the range of resources available for the fabrication of new materials, including particles and fibres with specific functionalities, 3D (bio)printed composites and organoids. Together, these advances lead to complex, multifunctional systems, which have many interesting potential applications, especially in the biomedical and bioengineering domains. Future exploration of the interactions between materials science and microfluidics will continue to enrich the diversity of applications across engineering as well as the physical and biomedical sciences.

}, url = {https://www.nature.com/articles/natrevmats201716}, author = {Hou, X. and Zhang, Y.S. and Trujillo-de Santiago, Grissel and Alvarez, M.M. and Ribas, J. and Jonas, S.J. and Weiss, P.S. and Andrews, A.M. and Aizenberg, J. and Khademhosseini, A.} } @article {988941, title = {Controlled growth and form of precipitating microstructures}, journal = {Science}, volume = {355}, year = {2017}, note = {

The authors thank J. A. Fritz, M. Kolle, M. Lončar, and
T. M. Schneider for fruitful discussions and P. A. Korevaar,
W. M. van Rees, J. C. Weaver, and T. C. Ferrante for technical assistance. This research was supported by NSF Designing Materials to Revolutionize and Engineer Our Future under award 15-33985, the Kavli Institute for Bionano Science and Technology at Harvard University, and the Harvard MRSEC under award 14- 20570. W.L.N. thanks the Netherlands Organization for Scientific Research (NWO) for financial support from a VENI grant. R.S. acknowledges Technical University Eindhoven{\textquoteright}s Fonds Ectspunten Buitenland financial support, and L.F. the Radboud University Nijmegen study fund. L. M. was partially supported by fellowships from the MacArthur Foundation and the Radcliffe Institute. Scanning and transmission electron microscopies were performed at the Center for Nanoscale Systems at Harvard University, supported by the NSF under award ECS-0335765, and the Amsterdam nanoCenter, supported by NWO. The authors declare no conflicts of interest.

}, pages = {1395-1399}, abstract = {

Controlled self-assembly of three-dimensional shapes holds great potential for fabrication of functional materials. Their practical realization requires a theoretical framework to quantify and guide the dynamic sculpting of the curved structures that often arise in accretive mineralization. Motivated by a variety of bioinspired coprecipitation patterns of carbonate and silica, we develop a geometrical theory for the kinetics of the growth front that leaves behind thin-walled complex structures. Our theory explains the range of previously observed experimental patterns and, in addition, predicts unexplored assembly pathways. This allows us to design a number of functional base shapes of optical microstructures, which we synthesize to demonstrate their light-guiding capabilities. Overall, our framework provides a way to understand and control the growth and form of functional precipitating microsculptures.

}, url = {http://science.sciencemag.org/content/355/6332/1395.long}, author = {C.N. Kaplan and W.L. Noorduin and Li, L. and R. Sadza and L. Folkertsma and Aizenberg, J. and L. Mahadevan} } @article {981141, title = {Photothermally triggered actuation of hybrid materials as a new platform for in vitro cell manipulation}, journal = {Nat. Commun.}, volume = {8}, year = {2017}, note = {

We thank Dr M. Aizenberg and Dr A. Grinthal for productive discussions. This research was supported by the DOE under award number DE-SC0005247 (the development of the dynamic material) and by the ONR under award number N00014-15-1-2157
(cell manipulation). A.S. acknowledges support from NSERC under award number PGS-S 389190-2010. T.S. acknowledges support from the Weizmann Institute of Science{\textemdash}National Postdoctoral Award Program for Advancing Women in Science. J.V.I.T. acknowledges support from the European Commission through the Seventh Framework Programme (FP7), project DynaSLIPS, project number 626954. Microstructure fabrication and electron microscopy were performed at the Center for Nanoscale Systems (CNS) at Harvard University, supported by the NSF under award number ECS-0335765.

}, pages = {14700}, abstract = {

Mechanical forces in the cell{\textquoteright}s natural environment have a crucial impact on growth,
differentiation and behaviour. Few areas of biology can be understood without taking into account how both individual cells and cell networks sense and transduce physical stresses. However, the field is currently held back by the limitations of the available methods to apply physiologically relevant stress profiles on cells, particularly with sub-cellular resolution, in controlled in vitro experiments. Here we report a new type of active cell culture material that allows highly localized, directional and reversible deformation of the cell growth substrate, with control at scales ranging from the entire surface to the subcellular, and response times on the order of seconds. These capabilities are not matched by any other method, and this versatile material has the potential to bridge the performance gap between the existing single cell micro-manipulation and 2D cell sheet mechanical stimulation techniques.

}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:32094141}, author = {Sutton, A and Shirman, T and Timonen, JVI and England, GT and Kim, P and Kolle, M and Ferrante, T and Zarzar, LD and Strong, E and Aizenberg, J} } @article {964731, title = {Harnessing structural instability and material instability in the hydrogel-actuated integrated responsive structures (HAIRS)}, journal = {Extreme Mechanics Letters}, volume = {13}, year = {2017}, note = {

This work was supported by the US Air Force Office of Scientific Research Multidisciplinary University Research Initiative under Award FA9550-09-1-0669-DOD35CAP. Dr. Yuhang Hu acknowledges the funds from National Science Foundation (Grant No. 1554326).

}, pages = {84-90}, abstract = {

We describe the behavior of a temperature-responsive hydrogel actuated integrated responsive structure (HAIRS). The structure is constructed by embedding a rigid high-aspect-ratio post in a layer of poly(Nisopropylacrylamide) (PNIPAM) hydrogel which is bonded to a rigid substrate. As the hydrogel contracts, the post abruptly tilts. The HAIRS has demonstrated its broad applications in generating reversible micropattern formation, active optics, tunable wettability, and artificial homeostasis. To quantitatively describe and predict the system behavior, we construct an analytical model combining the structural instability, i.e. buckling of the post, and the material instability, i.e. the volume phase transition of PNIPAM hydrogel. The two instabilities of the system result in a large hysteresis in response to heating and cooling processes. Experimental results validate the predicted phenomenon of the abrupt tilting as temperature and large hysteresis in a heating-and-cooling cycle in the PNIPAM actuated HAIRS. Based on this model, we further discuss the influence of the material properties on the actuation of the structure.

}, author = {Hu, Y. and Kim, P. and Aizenberg, J} } @article {952911, title = {Bacterial Interactions with Immobilized Liquid Layer}, journal = {Adv. Healthcare Mater.}, volume = {6}, year = {2017}, note = {

Y.K. and I.S. contributed equally to this work. The authors thank Ronn Friedlander for providing the E. coli Δ iC mutant, Phil Kim for helpful advice, and Abigail Weigang for editing assistance. J.V.I.T. thanks the European Commission for support through the Seventh Framework Programme (FP7) Project DynaSLIPS 626954. This material was based upon work supported by the Defense Advanced Research Projects Agency Grant N66001-11-1-4180 and Contract HR0011-13-C-0025.

}, pages = {1600948}, abstract = {

Bacterial interactions with surfaces are at the heart of many infection-related problems in healthcare. In this work, the interactions of clinically relevant bacteria with immobilized liquid (IL) layers on oil-infused polymers are investigated. Although oil-infused polymers reduce bacterial adhesion in all cases, complex interactions of the bacteria and liquid layer under orbital flow conditions are uncovered. The number of adherent Escherichia coli cells over multiple removal cycles increases in flow compared to static growth conditions, likely due to a disruption of the liquid layer continuity. Surprisingly, however, biofilm formation appears to remain low regardless of growth conditions. No incorporation of the bacteria into the layer is observed. Bacterial type is also found to affect the number of adherent cells, with more E. coli remaining attached under dynamic orbital flow than Staphylococcus aureus, Pseudomonas aeruginosa under identical conditions. Tests with mutant E. coli lacking flagella confirm that flagella play an important role in adhesion to these surfaces. The results presented here shed new light on the interaction of bacteria with IL layers, highlighting the fundamental differences between oil-infused and traditional solid interfaces, as well as providing important information for their eventual translation into materials that reduce bacterial adhesion in medical applications.

}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adhm.201600948}, author = {Kovalenko, Y and Sotiri, I and Timonen, JVI and Overton, JC and Homes, G and Aizenberg, J and Howell, C} } @article {927361, title = {An immobilized liquid interface prevents device associated bacterial infection in vivo}, journal = {Biomaterials}, volume = {113}, year = {2017}, note = {

The authors acknowledge support from the Defense Advanced Research Projects Agency Grant N66001-11-1-4180 and Contract HR0011-13-C-0025. This work was also in part funded by NIH T32 HL 008843-21A1 and the American College of Surgeons Resident Research Scholarship to Madhukar S. Patel as well as NIH T35 HL 110843 to Katherine A. Moravec. We thank the members of the Dr. Chaikof and Dr. Aizenberg lab for helpful discussions, as well as Jaakko Timonen and Thomas Ferrante for confocal microscopy assistance. We also thank the research and animal facilities at BIDMC and the Wyss Institute.

}, month = {September 2016}, pages = {80-92}, abstract = {

Virtually all biomaterials are susceptible to biofilm formation and, as a consequence, device-associated infection. The concept of an immobilized liquid surface, termed slippery liquid-infused porous surfaces (SLIPS), represents a new framework for creating a stable, dynamic, omniphobic surface that displays ultralow adhesion and limits bacterial biofilm formation. A widely used biomaterial in clinical care, expanded polytetrafluoroethylene (ePTFE), infused with various perfluorocarbon liquids generated SLIPS surfaces that exhibited a 99\% reduction in S. aureus adhesion with preservation of macrophage viability, phagocytosis, and bactericidal function. Notably, SLIPS modification of ePTFE prevents device infection after S. aureus challenge in\ vivo, while eliciting a significantly attenuated innate immune response. SLIPS-modified implants also decrease macrophage inflammatory cytokine expression in\ vitro, which likely contributed to the presence of a thinner fibrous capsule in the absence of bacterial challenge. SLIPS is an easily implementable technology that provides a promising approach to substantially reduce the risk of device infection and associated patient morbidity, as well as health care costs.

}, author = {Chen, J and Howell, C and Haller, CA and Patel, MS and Ayala, P and Moravec, KA and Dai, E and Liu, L and Sotiri, I and Aizenberg, M and Aizenberg, J and Chaikof, E} } @article {952796, title = {Characterization of a Mechanically Tunable Gyroid Photonic Crystal Inspired by the Butterfly Parides Sesostris}, journal = {Adv. Optical Mater.}, volume = {4}, year = {2016}, note = {

The authors thank Nick Cole for construction of the custom-made compression device used in the microwave spectroscopy experiments and Dr. Maik Scherer for providing a customized MATLAB code for the rendering of virtual gyroid models. C.P. acknowledges financial support from The University of Exeter EPSRC DTA. M.K. acknowledges financial support from the Alexander von Humboldt Foundation in the form of a Feodor-Lynen Postdoctoral Research Fellowship. P.V. and J.A. acknowledge financial support from AFOSR Multidisciplinary University Research Initiative under FA9550-10-1-0020 and FA9550-09-1-0669- DOD35CAP. This work was performed in part at Harvard University{\textquoteright}s Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Infrastructure Network (NNIN), which is supported by the National Science Foundation under NSF award no. ECS-0335765.

}, pages = {99-105}, abstract = {A mechanically tunable macroscale replica of the gyroid photonic crystal\ found in the\ Parides sesostris\ butterfly{\textquoteright}s wing scales is systematically characterized. By monitoring both photonic frequency changes and the distribution of stress fields within the compressed structure, electromagnetic transmission features are found and can be frequency-tuned and the structure only contains localized high stress fields when highly compressed.}, author = {Pouya, C. and Overvelde, J.T.B. and Kolle, M. and Aizenberg, J. and Bertoldi, K. and J. C. Weaver and P. Vukusic} } @article {952881, title = {Computational modeling of oscillating fins that {\textquotedblleft}catch and release{\textquotedblleft} targeted nanoparticles in bilayer flows}, journal = {Soft Matter}, volume = {12}, year = {2016}, note = {

The authors gratefully acknowledge financial support from the DOE through grant number DE-SC0005247.

}, pages = {1374-1384}, abstract = {

A number of physiological processes in living organisms involve the selective {\textquoteleft}{\textquoteleft}catch and release{\textquoteright}{\textquoteright} of biomolecules. Inspired by these biological processes, we use computational modeling to design synthetic systems that can controllably catch, transport, and release specific molecules within the surrounding solution, and, thus, could be harnessed for effective separation processes within microfluidic devices. Our system consists of an array of oscillating, microscopic fins that are anchored onto the floor of a microchannel and immersed in a flowing bilayer fluid. The oscillations drive the fins to repeatedly extend into the upper fluid and then tilt into the lower stream. The fins exhibit a specified wetting interaction with the fluids and specific adhesive interactions with nanoparticles in the solution. With this setup, we determine conditions where the oscillating fins can selectively bind, and thus, {\textquoteleft}{\textquoteleft}catch{\textquoteright}{\textquoteright} target nanoparticles within the upper fluid stream and
then release these particles into the lower stream. We isolate the effects of varying the wetting interaction and the fins{\textquoteright} oscillation modes on the effective extraction of target species from the upper stream. Our findings provide fundamental insights into the system{\textquoteright}s complex dynamics and yield guidelines for fabricating devices for the detection and separation of target molecules from complex fluids.

}, author = {Liu, Y. and Bhattacharya, A and Kuksenok, O and He, X and Aizenberg, M and Aizenberg, J and Balazs, AC} } @article {952876, title = {Extremely Stretchable and Fast Self-Healing Hydrogels}, journal = {Adv. Mater.}, volume = {28}, year = {2016}, note = {

I.J. was financially supported by Chonnam National University, 2013. J.C. thanks the support of the Leibniz Research Cluster under Award No. 419313. The study was performed in part at the Materials Research Science and Engineering Center at Harvard University, which was\ supported by the National Science Foundation under Award No. DMR- 14-20570. Support by the National Science Foundation through Grant No. CMMI-1404653 is also acknowledged.

}, pages = {4678-4683}, abstract = {Dynamic crosslinking of extremely stretchable hydrogels with rapid self-healing ability\ is described. Using this new strategy, the obtained hydrogels are able to elongate 100 times compared to their initial length and to completely self-heal within 30 s without external energy input.}, author = {Jeon, I and Cui, J and Illeperuma, WRK and Aizenberg, J and Vlassak, JJ} } @article {952841, title = {Harnessing Cooperative Interactions between Thermoresponsive Aptamers and Gels To Trap and Release Nanoparticles}, journal = {ACS Appl. Mater. Interfaces}, volume = {8}, year = {2016}, note = {

This work was supported by Department of Energy under the Award number DE-SC0005247.

}, pages = {30475-30483}, abstract = {

We use computational modeling to design a device that can controllably trap and release particles in solution in response to variations in temperature. The system exploits the thermoresponsive properties of end-grafted fibers and the underlying gel substrate. The fibers mimic the temperature-dependent behavior of biological aptamers, which form a hairpin structure at low temperatures (T) and unfold at higher T, consequently losing their binding affinity. The gel substrate exhibits a lower critical solution temperature and thus, expands at low temperatures and contracts at higher T. By developing a new dissipative particle dynamics simulation, we examine the behavior of this hybrid system in a flowing fluid that contains buoyant nanoparticles. At low T, the expansion of the gel causes the hairpin-shaped fibers to extend into the path of the fluid-driven particle. Exhibiting a high binding affinity for these particles at low temperature, the fibers effectively trap and extract the particles from the surrounding solution. When the temperature is increased, the unfolding of the fiber and collapse of the supporting gel layer cause the particles to be released and transported away from the layer by the applied shear flow. Since the temperature-induced conformational changes of the fiber and polymer gel are reversible, the system can be used repeatedly to {\textquotedblleft}catch and release{\textquotedblright} particles in solution. Our findings provide guidelines for creating fluidic devices that are effective at purifying contaminated solutions or trapping cells for biological assays.

}, author = {Liu, Y. and Kuksenok, O and He, X and Aizenberg, M and Aizenberg, J and Balazs, AC} } @article {952866, title = {Infused polymers for cell sheet release}, journal = {Scientific Reports}, volume = {6}, year = {2016}, note = {

e authors thank Ms. Nadine Haymour and Dr. Michael Aizenberg for important observations and editing assistance, Dr. Jaakko Timonen for the silicone oil dye, Mr. omas Ferrante for microscopy assistance, and Drs. Yevgeny Bruno and Francesco Pasqualini for enlightening discussions. is material is based upon work supported by the Defense Advanced Research Projects Agency Grant N66001-11-1-4180 and Contract HR0011- 13-C-0025.

}, pages = {26109}, abstract = {

Tissue engineering using whole, intact cell sheets has shown promise in many cell-based therapies. However, current systems for the growth and release of these sheets can be expensive to purchase or difficult to fabricate, hindering their widespread use. Here, we describe a new approach to cell sheet release surfaces based on silicone oil-infused polydimethylsiloxane. By coating the surfaces with a layer of fibronectin (FN), we were able to grow mesenchymal stem cells to densities comparable to those of tissue culture polystyrene controls (TCPS). Simple introduction of oil underneath an edge of the sheet caused it to separate from the substrate. Characterization of sheets post-transfer showed that they retain their FN layer and morphology, remain highly viable, and are able to grow and proliferate normally after transfer. We expect that this method of cell sheet growth and detachment may be useful for low-cost, flexible, and customizable production of cellular layers for tissue engineering.

}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:27662258}, author = {Juthani, N and Howell, C and Ledoux, H and Sotiri, I and Kelso, S and Kovalenko, Y and Tajik, A and Vu, TL and Lin, JJ and Sutton, A and Aizenberg, J} } @article {952871, title = {Micropatterned Hydrogel Surface with High-Aspect-Ratio Features for Cell Guidance and Tissue Growth}, journal = {ACS Appl. Mater. Interfaces}, volume = {8}, year = {2016}, note = {

This work was supported by the NSF Materials Research Science and Engineering Center (MRSEC) at Harvard University under Award DMR 14-20570. Y.H. thanks Dr. Yolanda Vasquez for teaching her the basics about cell culture.

}, pages = {21939-21945}, abstract = {

Surface topography has been introduced as a new tool to coordinate cell selection, growth, morphology, and differentiation. The materials explored so far for making such
structural surfaces are mostly rigid and impermeable. Hydrogel, on the other hand, was proved a better synthetic media for cell culture because of its biocompatibility, softness, and high permeability. Herein, we fabricated a poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogel substrate with high-aspectratio surface microfeatures. Such structural surface could effectively guide the orientation and shape of human mesenchymal stem cells (HMSCs). Notably, on the flat hydrogel surface, cells rounded up, whereas on the microplate patterned hydrogel surface, cells elongated and aligned along the direction parallel to the plates. The microplates were 2 μm thick, 20 μm tall, and 10-50 μm wide. The interplate spacing was 5-15 μm, and the intercolumn spacing was 5 μm. The elongation of cell body was more pronounced on the patterns with narrower interplate spacing and wider plates. The cells behaved like soft solid. The competition between surface energy and elastic energy defined the shape of the cells on the structured surfaces. The soft permeable hydrogel scaffold with surface structures was also demonstrated as being viable for longterm cell culture, and could be used to generate interconnected tissues with finely tuned cell morphology and alignment across a few centimeter sizes.

}, author = {Hu, Y. and You, J-O and Aizenberg, J} } @article {952886, title = {Tailoring re-entrant geometry in inverse colloidal monolayers to control surface wettability}, journal = {J. Mater. Chem. A}, volume = {4}, year = {2016}, note = {

N. V. acknowledges funding of the Deutsche Forschungsgemeinschaft (DFG) through the Cluster of Excellence Engineering of Advanced Materials. S. U., acknowledges the Deutsche Forschungsgemeinscha (DFG) for nancial support.

}, pages = {6853-6859}, abstract = {

Controlling the microscopic wetting state of a liquid in contact with a structured surface is the basis for the design of liquid repellent as well as anti-fogging coatings by preventing or enabling a given liquid to infiltrate the surface structures. Similarly, a liquid can be confined to designated surface areas by locally controlling the wetting state, with applications ranging from liquid transport on a surface to creating tailored microenvironments for cell culture or chemical synthesis. The control of the wetting of a low-surfacetension liquid is substantially more difficult compared to water and requires surface structures with overhanging features, known as re-entrant geometries. Here, we use colloidal self-assembly and templating to create two-dimensional nanopore arrays with tailored re-entrant geometry. These pore arrays, termed inverse monolayers, are prepared by backfilling a sacrificial colloidal monolayer with a silica sol{\textendash}gel precursor material. Varying the precursor concentration enables us to control the degree to which the colloids are embedded into the silica matrix. Upon calcination, nanopores with different opening angles result. The pore opening angle directly correlates with the re-entrant curvature of the surface nanostructures and can be used to control the macroscopic wetting behavior of a liquid sitting on the surface structures. We characterize the wetting of various liquids by static and dynamic contact angles and find correlation between the experimental results and theoretical predictions of the wetting state based on simple geometric considerations. We demonstrate the creation of omniphobic surface coatings that support Cassie{\textendash}Baxter wetting states for liquids with low surface tensions, including octane (g {\textonequarter} 21.7 mN m1). We further use photolithography to spatially confine such low-surface-tension liquids to desired areas of the substrate with high accuracy.

}, author = {Utech, S and Bley, K and Aizenberg, J and Vogel, N} } @article {914086, title = {Transparent antifouling material for improved operative field visibility in endoscopy}, journal = {Proc. Nat. Acad. Sci.}, volume = {113}, year = {2016}, note = {

We thank Dr. M. Aizenberg for helpful discussions; M. Duffy, F. Connolly, and B. Weinstein for assistance with image analysis; and C. Zhang for the algae solution. S.S. thanks the Natural Sciences and Engineering Research Council (NSERC) of Canada for financial support. N.V. acknowledges funding by the Deutsche Forschungsgemeinschaft through the Cluster of Excellence (EXC 315) and the Interdisciplinary Center for Func- tional Particle Systems (FPS) at Friedrich-Alexander University Erlangen- Nürnberg. This work was supported by the Wyss Institute for Biologically Inspired Engineering at Harvard University and National Science Foundation (NSF) Materials Research Science and Engineering Centers (MRSEC) Grant DMR-1420570.

}, month = {2016}, pages = {11676-11681}, abstract = {

Inspection devices are frequently occluded by highly contaminating fluids that disrupt the visual field and their effective operation. These issues are particularly striking in endoscopes, where the diagnosis and treatment of diseases are compromised by the obscuring of the operative field by body fluids. Here we demonstrate that the application of a liquid-infused surface coating strongly repels sticky biological secretions and enables an uninterrupted field of view. Extensive bronchoscopy procedures performed in vivo on a porcine model shows significantly reduced fouling, resulting in either unnecessary or \~{}10{\textendash}15 times shorter and less intensive lens clearing procedures compared with an untreated endoscope.

Camera-guided instruments, such as endoscopes, have become an essential component of contemporary medicine. The 15{\textendash}20 million endoscopies performed every year in the United States alone demonstrate the tremendous impact of this technology. However, doctors heavily rely on the visual feedback provided by the endoscope camera, which is routinely compromised when body fluids and fogging occlude the lens, requiring lengthy cleaning procedures that include irrigation, tissue rubbing, suction, and even temporary removal of the endoscope for external cleaning. Bronchoscopies are especially affected because they are performed on delicate tissue, in high-humidity environments with exposure to extremely adhesive biological fluids such as mucus and blood. Here, we present a repellent, liquid-infused coating on an endoscope lens capable of preventing vision loss after repeated submersions in blood and mucus. The material properties of the coating, including conformability, mechanical adhesion, transparency, oil type, and biocompatibility, were optimized in comprehensive in vitro and ex vivo studies. Extensive bronchoscopy procedures performed in vivo on porcine lungs showed significantly reduced fouling, resulting in either unnecessary or \~{}10{\textendash}15 times shorter and less intensive lens clearing procedures compared with an untreated endoscope. We believe that the material developed in this study opens up opportunities in the design of next-generation endoscopes that will improve visual field, display unprecedented antibacterial and antifouling properties, reduce the duration of the procedure, and enable visualization of currently unreachable parts of the body, thus offering enormous potential for disease diagnosis and treatment.

}, author = {Sunny, S. and Cheng, G. and D. Daniel and Lo, P. and Ochoa, S. and Howell, C. and Vogel, N. and Majid, A. and Aizenberg, J.} } @article {865776, title = {A Constructive Chemical Conversation}, journal = {American Scientist}, volume = {104}, year = {2016}, month = {Jul-Aug 2016}, pages = {228-235}, abstract = {

Using simple ingredients and processing, the authors discuss how they create vastly complex three-dimensional structures that assemble themselves.

}, url = {http://dx.doi.org/10.1511/2016.121.228}, author = {Grinthal, A. and W.L. Noorduin and Aizenberg, J.} } @article {851806, title = {Bioinspired Artificial Melanosomes As Colorimetric Indicators of Oxygen Exposure}, journal = {ACS Appl. Mater. Interfaces}, volume = {8}, year = {2016}, note = {

C.S. acknowledges that this material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. DGE1342536. I.B.B. acknowledges support from a Banting Postdoctoral Fellowship funded by the Natural Sciences and Engineering Research Council of Canada.

}, month = {Feb 18, 2016}, pages = {4314-4317}, abstract = {

Many industries require irreversibly responsive materials for use as sensors or detectors of environmental exposure. We describe the synthesis and fabrication of a nontoxic surface coating that reports oxygen exposure of the substrate material through irreversible formation of colored spots. The coating consists of a selectively permeable rubber film that contains the colorless organic precursors to darkly pigmented synthetic melanin. Melanin synthesis within the film is triggered by exposure to molecular oxygen. The selectively permeable rubber film regulates the rate of oxygen diffusion, enabling independent control of the sensitivity and response time of the artificial melanosome, while preventing leaching of melanin or its precursors.

}, author = {C. Shillingford and Russell, C.W. and Burgess, I.B. and Aizenberg, J.} } @article {837611, title = {A colloidoscope of colloid-based porous materials and their uses}, journal = {Chem. Soc. Rev.}, volume = {45}, year = {2016}, note = {This work was supported by the NSF Materials Research Science and Engineering Center (MRSEC) at Harvard University under Award No. DMR 14-20570 and by AFOSR under Award No. FA9550-09-1-0669-DOD35CA. The authors wish to thank Alison Grinthal for fruitful discussions. KRP acknowledges the support of a National Defense Science and Engineering Graduate Fellowship from the Department of Defense; TS acknowledges support from the Weizmann Institute of Science {\textendash} National Postdoctoral Award Program for Advancing Women in Science. NV acknowledges funding from the Deutsche Forschungsgemeinschaft through the Cluster of Excellence Engineering of Advanced Materials.}, pages = {281-322}, abstract = {Nature evolved a variety of hierarchical structures that produce sophisticated functions. Inspired by these natural materials, colloidal self-assembly provides a convenient way to produce structures from simple building blocks with a variety of complex functions beyond those found in nature. In particular, colloid-based porous materials (CBPM) can be made from a wide variety of materials. The internal structure of CBPM also has several key attributes, namely porosity on a sub-micrometer length scale, interconnectivity of these pores, and a controllable degree of order. The combination of structure and composition allow CBPM to attain properties important for modern applications such as photonic inks, colorimetric sensors, self-cleaning surfaces, water purification systems, or batteries. This review summarizes recent developments in the field of CBPM, including principles for their design, fabrication, and applications, with a particular focus on structural features and materials{\textquoteright} properties that enable these applications. We begin with a short introduction to the wide variety of patterns that can be generated by colloidal self-assembly and templating processes. We then discuss different applications of such structures, focusing on optics, wetting, sensing, catalysis, and electrodes. Different fields of applications require different properties, yet the modularity of the assembly process of CBPM provides a high degree of tunability and tailorability in composition and structure. We examine the significance of properties such as structure, composition, and degree of order on the materials{\textquoteright} functions and use, as well as trends in and future directions for the development of CBPM.}, doi = {10.1039/C5CS00533G}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:31759927}, author = {Phillips, K.R. and England, G.T. and Sunny, S. and Shirman, E. and Shirman, T. and Vogel, N. and Aizenberg, J.} } @article {837626, title = {Condensation on slippery asymmetric bumps}, journal = {Nature}, volume = {531}, year = {2016}, note = {We thank M. Khan, J. Alvarenga, D. Daniel, S. H. Kang, M. Hoang, and J. Timonen for discussions and technical assistance. This research was supported by the Department of Energy/ARPA-E award number DE-AR0000326. N.H. thanks the Research Experiences for Undergraduates programme supported by the National Science Foundation award number DMR-1420570.}, pages = {78-82}, abstract = {Controlling dropwise condensation is fundamental to water-harvesting systems, desalination, thermal power generation, air conditioning, distillation towers, and numerous other applications. For any of these, it is essential to design surfaces that enable droplets to grow rapidly and to be shed as quickly as possible.\ However, approaches\ based on microscale, nanoscale or molecular-scale textures suffer from intrinsic trade-offs that make it difficult to optimize both growth and transport at once. Here we present a conceptually different design approach{\textemdash}based on principles derived from Namib desert beetles, cacti, and pitcher plants{\textemdash}that synergistically combines these aspects of condensation and substantially outperforms other synthetic surfaces. Inspired by an unconventional interpretation of the role of the beetle{\textquoteright}s bumpy surface geometry in promoting condensation, and using theoretical modelling, we show how to maximize vapour diffusion flux at the apex of convex millimetric bumps by optimizing the radius of curvature and cross-sectional shape. Integrating this apex geometry with a widening slope, analogous to cactus spines, directly couples facilitated droplet growth with fast directional transport, by creating a free-energy profile that drives the droplet down the slope before its growth rate can decrease. This coupling is further enhanced by a slippery, pitcher-plant-inspired nanocoating that facilitates feedback between coalescence-driven growth and capillary-driven motion on the way down. Bumps that are rationally designed to integrate these mechanisms are able to grow and transport large droplets even against gravity and overcome the effect of an unfavourable temperature gradient. We further observe an unprecedented sixfold-higher exponent of growth rate, faster onset, higher steady-state turnover rate, and a greater volume of water collected compared to other surfaces. We envision that this fundamental understanding and rational design strategy can be applied to a wide range of water-harvesting and phase-change heat-transfer applications.}, doi = {10.1038/nature16956}, author = {K.-C. Park and Kim, P. and Grinthal, A. and N. He and D. Fox and J. C. Weaver and Aizenberg, J.} } @article {837631, title = {Design of anti-icing surfaces: smooth, textured or slippery?}, journal = {Nat. Rev. Mater.}, volume = {1}, year = {2016}, note = {The authors thank A. Grinthal and K.-C. Park for their comments on the manuscript. M.J.K. thanks Natural Sciences and Engineering Research Council (NSERC) for a Postgraduate Scholarships-Doctoral (PGS D) scholarship. The information, data, or work presented herein was funded in part by the Advanced Research Projects Agency-Energy (ARPA-E), US Department of Energy, under Award Number DE-AR0000326.}, pages = {15003}, abstract = {Passive anti-icing surfaces, or icephobic surfaces, are an area of great interest because of their significant economic, energy and safety implications in the prevention and easy removal of ice in many facets of society. The complex nature of icephobicity, which requires performance in a broad range of icing scenarios, creates many challenges when designing ice-repellent surfaces. Although superhydrophobic surfaces incorporating micro- or nanoscale roughness have been shown to prevent ice accumulation under certain conditions, the same roughness can be detrimental in other environments. Surfaces that present a smooth liquid interface can eliminate some of the drawbacks of textured superhydrophobic surfaces, but additional study is needed to fully realize their potential. As attention begins to shift towards alternative anti-icing strategies, it is important to consider and to understand the nature of ice repellency in all environments to identify the limitations of current solutions and to design new materials with robust icephobicity.}, doi = {10.1038/natrevmats.2015.3}, author = {M.J. Kreder and J. Alvarenga and Kim, P. and Aizenberg, J.} } @article {837621, title = {Tuning and Freezing Disorder in Photonic Crystals using Percolation Lithography}, journal = {Scientific Reports}, volume = {6}, year = {2016}, note = {The authors thank Mackenzie Kinney, Kevin Raymond, Natalie Koay, Sofia Magkiriadou, Dr. Caitlin Howell, and Prof. Mathias Kolle for helpful discussions. This work was supported by the US Air Force Office of Scientific Research Multidisciplinary University Research Initiative under Award FA9550-09-1-0669-DOD35CAP (optical properties), and by the US Federal Railroad Administration under contract number DTFR5314C00015 (volatility analysis). IBB acknowledges support from a Banting Postdoctoral Fellowship funded by the Natural Sciences and Engineering Research Council of Canada.}, pages = {19542}, abstract = {Although common in biological systems, synthetic self-assembly routes to complex 3D photonic structures with tailored degrees of disorder remain elusive. Here we show how liquids can be used to finely control disorder in porous 3D photonic crystals, leading to complex and hierarchical geometries. In these optofluidic crystals, dynamically tunable disorder is superimposed onto the periodic optical structure through partial wetting or evaporation. In both cases, macroscopic symmetry breaking is driven by subtle sub-wavelength variations in the pore geometry. These variations direct site-selective infiltration of liquids through capillary interactions. Incorporating cross-linkable resins into our liquids, we developed methods to freeze in place the filling patterns at arbitrary degrees of partial wetting and intermediate stages of drying. These percolation lithography techniques produced permanent photonic structures with adjustable disorder. By coupling strong changes in optical properties to subtle differences in fluid behavior, optofluidic crystals may also prove useful in rapid analysis of liquids.}, doi = {10.1038/srep19542}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:24984018}, author = {Burgess, I.B. and Abedzadeh, N. and Kay, T.M. and Shneidman, A.V. and Cranshaw, D.J. and Loncar, M. and Aizenberg, J.} } @article {951741, title = {Designing a gel{\textendash}fiber composite to extract nanoparticles from solution}, journal = {Soft Matter}, volume = {11}, year = {2015}, note = {

ACB and JA are grateful for financial support from DOE DESC0005247 to develop the computational model and ONR N00014-15-1-2306 to probe anti-fouling applications of the coating.

}, pages = {8692-8700}, abstract = {

The extraction of nanoscopic particulates from flowing fluids is a vital step in filtration processes, as well as the fabrication of nanocomposites. Inspired by the ability of carnivorous plants to use hair-like filaments to entrap species, we use computational modeling to design a multi-component system that integrates compliant fibers and thermo-responsive gels to extract particles from the surrounding solution. In particular, hydrophobic fibers are embedded in a gel that exhibits a lower critical solution temperature (LCST). With an increase in temperature, the gel collapses to expose fibers that self assemble into bundles, which act as nanoscale {\textquoteleft}{\textquoteleft}grippers{\textquoteright}{\textquoteright} that bind the particles and draw them into the underlying gel. By varying the relative stiffness of the fibers, the fiber{\textendash}particle interaction strength and the shear rate in the solution, we identify optimal parameters where the particles are effectively drawn from the solution and remain firmly bound within the gel layer. Hence, the system can be harnessed in purifying fluids and creating novel hybrid materials that integrate nanoparticles with polymer gels.

}, author = {Liu, Y. and Yong, X. and McFarlin IV, G. and Kuksenok, O. and Aizenberg, J. and Balazs, A.C.} } @article {951656, title = {Elastocapillary coalescence of plates and pillars}, journal = {Proc. R. Soc. A.}, volume = {471}, year = {2015}, note = {

We thank the Harvard-MRSEC DMR-0820484, the MacArthur Foundation (LM), and the NRF of Korea (Grant No. 2013034978, H.-Y.K.) for support.

}, pages = {20140593}, abstract = {

When a fluid-immersed array of supported plates or pillars is dried, evaporation leads to the formation of menisci on the tips of the plates or pillars that bring them together to form complex patterns. Building on prior experimental observations, we use a combination of theory and computation to understand the nature of this instability and its evolution in both the two- and three-dimensional setting of the problem. For the case of plates, we explicitly derive the interaction torques based on the relevant physical parameters associated with pillar deformation, contact-line pinning/depinning and fluid volume changes. A Bloch-wave analysis for our periodic mechanical system captures the window of volumes where the two-plate eigenvalue characterizes the onset of the coalescence instability. We then study the evolution of these binary clusters and their eventual elastic arrest using numerical simulations that account for evaporative dynamics coupled to capillary coalescence. This explains both the formation of hierarchical clusters and the sensitive dependence of the final structures on initial perturbations, as seen in our experiments. We then generalize our analysis to treat the problem of pillar collapse in three dimensions, where the fluid domain is completely connected and the interface is a minimal surface with the uniform mean curvature. Our theory and simulations capture the salient features of experimental observations in a range of different situations and may thus be useful in controlling the ensuing patterns.

}, author = {Wei, Z. and Schneider, T.M. and Kim, J. and Kim, H.-J. and Aizenberg, J. and L. Mahadevan} } @article {952761, title = {Role of Flagella in Adhesion of Escherichia coli to Abiotic Surfaces}, journal = {Langmuir}, volume = {31}, year = {2015}, note = {

We thank Tanya Shirman for TEM imaging, Hera Vlamakis for her help with phage transduction, Matthew Cabeen for his assistance with large-scale cultures for purification, and Karen Fahrner for assistance with flagella purification protocols. This work was partially funded by the Office of Naval Research under Award N00014-11-1-0641.

}, pages = {6137-6144}, abstract = {

Understanding the interfacial activity of bacteria is of critical importance due to the huge economic and public health implications associated with surface fouling and biofilm formation. The complexity of the process and difficulties of predicting microbial adhesion to novel materials demand study of the properties of specific bacterial surface features and their potential contribution to surface attachment. Here, we examine flagella, cell appendages primarily studied for their cell motility function, to elucidate their potential role in the surface adhesion of Escherichia coli - a model organism and potential pathogen. We use self-assembled monolayers (SAMs) of thiol-bearing molecules on gold films to generate surfaces of varying hydrophobicity, and measure adhesion of purified flagella using quartz crystal microbalance. We show that flagella adhere more extensively and bind more tightly to hydrophobic SAMs than to hydrophilic ones, and we propose a two-step vs a single-step adhesion mechanism that accounts for the observed dissipation and frequency changes for the two types of surfaces, respectively. Subsequently, study of the adhesion of wild-type and flagella knockout cells confirms that flagella improve adhesion to hydrophobic substrates, whereas cells lacking flagella do not show preferred affinity to hydrophobic substrates. Together, these properties bring about an interesting ability of cells with flagella to stabilize emulsions of aqueous culture and dodecane, not observed for cells lacking flagella. This work contributes to our overall understanding of nonspecific bacterial adhesion and confirms that flagella, beyond motility, may play an important role in surface adhesion.

}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:33204050}, author = {R.S. Friedlander and Vogel, N. and Aizenberg, J.} } @article {837576, title = {An aptamer-functionalized chemomechanically modulated biomolecule catch-and-release system}, journal = {Nat. Chem.}, volume = {7}, year = {2015}, note = {This work was supported by the Department of Energy under Award No. DE-SC0005247. We thank M. Krogsgaard and C. Howell for their help with the XPS characterization of the aptamer functionalization of the microstructures.}, pages = {447-454}, abstract = {The efficient extraction of (bio)molecules from fluid mixtures is vital for applications ranging from target characterization in (bio)chemistry to environmental analysis and biomedical diagnostics. Inspired by biological processes that seamlessly synchronize the capture, transport and release of biomolecules, we designed a robust chemomechanical sorting system capable of the concerted catch and release of target biomolecules from a solution mixture. The hybrid system is composed of target-specific, reversible binding sites attached to microscopic fins embedded in a responsive hydrogel that moves the cargo between two chemically distinct environments. To demonstrate the utility of the system, we focus on the effective separation of ​thrombin\ by synchronizing the pH-dependent binding strength of a ​thrombin-specific aptamer with volume changes of the pH-responsive hydrogel in a biphasic microfluidic regime, and show a non-destructive separation that has a quantitative sorting efficiency, as well as the system{\textquoteright}s stability and amenability to multiple solution recycling.}, doi = {10.1038/NCHEM.2203}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:33204049}, author = {Shastri, A. and McGregor, L.M. and Liu, Y. and Harris, V. and Nan, H. and Mujica, M. and Vasquez, Y. and Bhattacharya, A. and Ma, Y. and Aizenberg, M. and Kuksenok, O. and Balazs, A.C. and Aizenberg, J. and He, X.} } @article {837596, title = {Color from hierarchy: Diverse optical properties of micron-sized spherical colloidal assemblies}, journal = {Proc. Nat. Acad. Sci.}, volume = {112}, year = {2015}, note = {This work was supported by the National Science Foundation Materials Research Science and Engineering Center at Harvard University under Award DMR-1420570 and by the Badische Anilin und Sodafabrik{\textquoteright}s North American Center for Research on Advanced Materials. N.V. acknowledges funding of the Deutsche Forschungsgemeinschaft (DFG) through the Cluster of Excellence Engineering of Advanced Materials. S.U. acknowledges funding from DFG. K.R.P. acknowledges support from a graduate research fellowship from the Department of Defense. I.B.B. acknowledges support from a Banting Postdoctoral Fellowship funded by the Natural Sciences and Engineering Research Council of Canada. M.K. acknowledges financial support from the Massachusetts Institute of Technology Mechanical Engineering Department.}, pages = {10845-10850}, abstract = {Materials in nature are characterized by structural order over multiple length scales have evolved for maximum performance and multifunctionality, and are often produced by self-assembly processes. A striking example of this design principle is structural coloration, where interference, diffraction, and absorption effects result in vivid colors. Mimicking this emergence of complex effects from simple building blocks is a key challenge for man-made materials. Here, we show that a simple confined self-assembly process leads to a complex hierarchical geometry that displays a variety of optical effects. Colloidal crystallization in an emulsion droplet creates micron-sized superstructures, termed photonic balls. The curvature imposed by the emulsion droplet leads to frustrated crystallization. We observe spherical colloidal crystals with ordered, crystalline layers and a disordered core. This geometry produces multiple optical effects. The ordered layers give rise to structural color from Bragg diffraction with limited angular dependence and unusual transmission due to the curved nature of the individual crystals. The disordered core contributes nonresonant scattering that induces a macroscopically whitish appearance, which we mitigate by incorporating absorbing gold nanoparticles that suppress scattering and macroscopically purify the color. With increasing size of the constituent colloidal particles, grating diffraction effects dominate, which result from order along the crystal{\textquoteright}s curved surface and induce a vivid polychromatic appearance. The control of multiple optical effects induced by the hierarchical morphology in photonic balls paves the way to use them as building blocks for complex optical assemblies{\textemdash}potentially as more efficient mimics of structural color as it occurs in nature.}, doi = {10.1073/pnas.1506272112}, url = {http://www.pnas.org/content/112/35/10845}, author = {Vogel, N. and S. Utech and England, G.T. and Shirman, T. and Phillips, K.R. and N. Koay and Burgess, I.B. and Kolle, M. and D. A. Weitz and Aizenberg, J.} } @article {837586, title = {Combining Bottom-Up Self-Assembly with Top-Down Microfabrication to Create Hierarchical Inverse Opals with High Structural Order}, journal = {Small}, volume = {11}, year = {2015}, note = {This work was supported by the National Science Foundation (NSF) Materials Research Science and Engineering Centers (MRSEC) at Harvard University under Award No. DMR 14{\textendash}20570. N.V. acknowl-edges funding from the Cluster of Excellence - Engineering of Advanced Materials.}, pages = {4334-4340}, abstract = {Colloidal particles can assemble into ordered crystals, creating periodically structured materials at the nanoscale without relying on expensive equipment. The combination of small size and high order leads to strong interaction with visible light, which induces macroscopic, iridescent structural coloration. To increase the complexity and functionality, it is important to control the organization of such materials in hierarchical structures with high degrees of order spanning multiple length scales. Here, a bottom-up assembly of polystyrene particles in the presence of a silica sol{\textendash}gel precursor material (tetraethylorthosilicate, TEOS), which creates crack-free inverse opal films with high positional order and uniform crystal alignment along the (110) crystal plane, is combined with top-down microfabrication techniques. Micrometer scale hierarchical superstructures having a highly regular internal nanostructure with precisely controlled crystal orientation and wall profiles are produced. The ability to combine structural order at the nano- and microscale enables the fabrication of materials with complex optical properties resulting from light{\textendash}matter interactions at different length scales. As an example, a hierarchical diffraction grating, which combines Bragg reflection arising from the nanoscale periodicity of the inverse opal crystal with grating diffraction resulting from a micrometer scale periodicity, is demonstrated.}, doi = {10.1002/smll.201500865}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:27417442}, author = {M. Schaffner and G. England and Kolle, M. and Aizenberg, J. and Vogel, N.} } @article {837591, title = {Dynamic polymer systems with self-regulated secretion for the control of surface properties and material healing}, journal = {Nat. Mater.}, volume = {14}, year = {2015}, note = {The work was supported by the DoE under award $\#$ DE-SC0005247 (polymer synthesis and self-repair) and the DoD Office of Naval Research under award N00014-11-1-0641 (wetting and anti-fouling properties). We thank J. Alvarenga for his help with the flow-cell design and measurements, and Y. Hu and M. Aizenberg for discussion.}, pages = {790-795}, abstract = {Approaches for regulated fluid secretion, which typically rely on fluid encapsulation and release from a shelled compartment, do not usually allow a fine continuous modulation of secretion, and can be difficult to adapt for monitoring or function-integration purposes. Here, we report self-regulated, self-reporting secretion systems consisting of liquid-storage compartments in a supramolecular polymer-gel matrix with a thin liquid layer on top, and demonstrate that dynamic liquid exchange between the compartments, matrix and surface layer allows repeated, responsive self-lubrication of the surface and cooperative healing of the matrix. Depletion of the surface liquid or local material damage induces secretion of the stored liquid via a dynamic feedback between polymer crosslinking, droplet shrinkage and liquid transport that can be read out through changes in the system{\textquoteright}s optical transparency. We foresee diverse applications in fluid delivery, wetting and adhesion control, and material\ self-repair.}, doi = {10.1038/nmat4325}, url = {https://www.nature.com/articles/nmat4325}, author = {Cui, J. and D. Daniel and Grinthal, A. and K. Lin and Aizenberg, J.} } @article {837601, title = {Dynamics of evaporative colloidal patterning}, journal = {Physics of Fluids}, volume = {27}, year = {2015}, note = {This research was supported by the Air Force Office of Scientific Research (AFOSR) under Award No. FA9550-09-1-0669-DOD35CAP, the Harvard-MRSEC DMR-1420570, and the Kavli Institute for Bionano Science and Technology at Harvard University.}, pages = {092105}, abstract = {

Drying\ suspensions\ often leave behind complex patterns of particulates, as might be seen in the coffee stains on a table. Here, we consider the\ dynamics\ of periodic band or uniform solid\ film\ formation on a vertical plate suspended partially in a drying\ colloidal\ solution.\ Direct observations allow us to visualize the\ dynamics\ of band and\ film\ deposition, where both are made of multiple layers of close packed particles. We further see that there is a transition between banding and filming when the\ colloidal\ concentration is varied. A minimal theory of the\ liquid\ meniscus\ motion along the plate reveals the\ dynamics\ of the banding and its transition to the filming as a function of the ratio of\ deposition\ and\ evaporation\ rates. We also provide a complementary multiphase\ model\ of\ colloids\ dissolved in the\ liquid,\ which couples the inhomogeneous\ evaporation\ at the evolving\ meniscus\ to the fluid and particulate flows and the transition from a dilute\ suspension\ to a porous plug. This allows us to determine the concentration dependence of the bandwidth and the\ deposition\ rate. Together, our findings allow for the control of drying-induced patterning as a function of the\ colloidal\ concentration and\ evaporationrate.

}, doi = {10.1063/1.4930283}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:23670482}, author = {C.N. Kaplan and N. Wu and S. Mandre and Aizenberg, J. and L. Mahadevan} } @article {837561, title = {A highly conspicuous mineralized composite photonic architecture in the translucent shell of the blue-rayed limpet}, journal = {Nat. Commun.}, volume = {6}, year = {2015}, note = {We gratefully acknowledge the help of Ruben Chapela, Christopher Earing, Edward Blum, Mathilde Bue and Stuart Jenkins with the collection of specimen. We thank Professor Ullrich Steiner and Dr Katherine Thomas for their support in the initial project stages and Dr Stefan Guldin for help with the whole-shell powder X-ray diffraction measurements (see Supplementary Information). We would like to thank Professor PUPA Gilbert and Ian Olson for general discussion, Dr Shiahn Chen and Dr Yong Zhang for their technical assistance in electron microscopy and Dr Steve Wang for his support at beamline 32-ID at the Advanced Photon Source. Pellucida morph and nudibranch photographs, displayed in Fig. 7 were kindly provided by Larry Friesen, Josep Lluis Peralta and Jim Anderson. M.K. and J.A. gratefully acknowledge the support of the US Air Force Office of Scientific Research Multidisciplinary University Research Initiative (FA9550-09-1-0669-DOD35- CAP). L.L. and C.O. gratefully acknowledge the support of the National Science Foundation MIT Center for Materials Science and Engineering (DMR-0819762), and the National Security Science and Engineering Faculty Fellowship Program (N00244-09-1- 0064). M.K. acknowledges the financial support from the Alexander von Humboldt Foundation in form of a Feodor Lynen postdoctoral research fellowship. Use of the Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357.}, pages = {6322}, abstract = {Many species rely on diverse selections of entirely organic photonic structures for the manipulation of light and the display of striking colours. Here we report the discovery of a mineralized hierarchical photonic architecture embedded within the translucent shell of the blue-rayed limpet\ Patella pellucida. The bright colour of the limpet{\textquoteright}s stripes originates from light interference in a periodically layered zig-zag architecture of crystallographically co-oriented calcite lamellae. Beneath the photonic multilayer, a disordered array of light-absorbing particles provides contrast for the blue colour. This unique mineralized manifestation of a synergy of two distinct optical elements at specific locations within the continuum of the limpet{\textquoteright}s translucent protective shell ensures the vivid shine of the blue stripes, which can be perceived under water from a wide range of viewing angles. The stripes{\textquoteright} reflection band coincides with the spectral range of minimal light absorption in sea water, raising intriguing questions regarding their functional significance.}, doi = {10.1038/ncomms7322}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:14351052}, author = {Li, L. and Kolle, S. and J. C. Weaver and Ortiz, C. and Aizenberg, J. and Kolle, M.} } @article {837566, title = {Liquid-based gating mechanism with tunable multiphase selectivity and antifouling behaviour}, journal = {Nature}, volume = {519}, year = {2015}, note = {This work was supported in part by the Advanced Research Projects Agency-Energy (ARPA-E), US Department of Energy, under award number DE-AR0000326. We thank M. Aizenberg, R. T. Blough and X. Y. Chen for discussions; A. B. Tesler for assistance with the scanning electron microscopy; and T. S. Wong, B. D. Hatton and R. A. Belisle for assistance with antifouling experiments.}, pages = {70-73}, abstract = {Living organisms make extensive use of micro- and nanometre-sized pores as gatekeepers for controlling the movement of fluids, vapours and solids between complex environments. The ability of such pores to coordinate multiphase transport, in a highly selective and subtly triggered fashion and without clogging, has inspired interest in synthetic gated pores for applications ranging from fluid processing to 3D printing and lab-on-chip systems. But although specific gating and transport behaviours have been realized by precisely tailoring pore surface chemistries and pore geometries,\ a single system capable of controlling complex, selective multiphase transport has remained a distant prospect, and fouling is nearly inevitable. Here we introduce a gating mechanism that uses a capillary-stabilized liquid as a reversible, reconfigurable gate that fills and seals pores in the closed state, and creates a non-fouling, liquid-lined pore in the open state. Theoretical modelling and experiments demonstrate that for each transport substance, the gating threshold{\textemdash}the pressure needed to open the pores{\textemdash}can be rationally tuned over a wide pressure range. This enables us to realize in one system differential response profiles for a variety of liquids and gases, even letting liquids flow through the pore while preventing gas from escaping. These capabilities allow us to dynamically modulate gas{\textendash}liquid sorting in a microfluidic flow and to separate a three-phase air{\textendash}water{\textendash}oil mixture, with the liquid lining ensuring sustained antifouling behaviour. Because the liquid gating strategy enables efficient long-term operation and can be applied to a variety of pore structures and membrane materials, and to micro- as well as macroscale fluid systems, we expect it to prove useful in a wide range of applications.}, doi = {10.1038/nature14253}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:27657493}, author = {Hou, X. and Hu, Y. and Grinthal, A. and Khan, M. and Aizenberg, J.} } @article {837556, title = {Liquid-Infused Silicone As a Biofouling-Free Medical Material}, journal = {ACS Biomater. Sci. Eng.}, volume = {1}, year = {2015}, note = {We thank Mr. Jack Alvarenga for materials and equipment management, as well as Gareth Holmes, Haylea Ledoux, and Carine Nemr for their help with the static biofilm studies. This work was supported in part by the Office of Naval Research under award no. N00014-11-1-0641.}, pages = {43-51}, abstract = {There is a dire need for infection prevention strategies that do not require the use of antibiotics, which exacerbate the rise of multi- and pan-drug resistant infectious organisms. An important target in this area is the bacterial attachment and subsequent biofilm formation on medical devices (e.g., catheters). Here we describe nonfouling, lubricant-infused slippery polymers as proof-of-concept medical materials that are based on oil-infused polydimethylsiloxane (iPDMS). Planar and tubular geometry silicone substrates can be infused with nontoxic silicone oil to create a stable, extremely slippery interface that exhibits exceptionally low bacterial adhesion and prevents biofilm formation. Analysis of a flow culture of\ Pseudomonas aeruginosa\ through untreated PDMS and iPDMS tubing shows at least an order of magnitude reduction of biofilm formation on iPDMS, and almost complete absence of biofilm on iPDMS after a gentle water rinse. The iPDMS materials can be applied as a coating on other polymers or prepared by simply immersing silicone tubing in silicone oil, and are compatible with traditional sterilization methods. As a demonstration, we show the preparation of silicone-coated polyurethane catheters and significant reduction of\ Escherichia coli\ and\ Staphylococcus epidermidis\ biofilm formation on the catheter surface. This work represents an important first step toward a simple and effective means of preventing bacterial adhesion on a wide range of materials used for medical devices.}, doi = {10.1021/ab5000578}, author = {MacCallum, N. and Howell, C. and Kim, P. and Sun, D. and Friedlander, R. and Ranisau, J. and Ahanotu, O. and Lin, J.J. and Vena, A. and Hatton, B. and T.-S. Wong and Aizenberg, J.} } @article {837616, title = {Multifunctionality of chiton biomineralized armor with an integrated visual system}, journal = {Science}, volume = {350}, year = {2015}, note = {We gratefully acknowledge support from the U.S. Army Research Office through the Massachusetts Institute of Technology (MIT) Institute for Soldier Nanotechnologies (contract W911NF-07-D- 0004) and the National Security Science and Engineering Faculty Fellowship Program (N00244-09-1-0064). This work made use of the Materials Research Science and Engineering Center Shared Experimental Facilities at MIT, supported by the National Science Foundation under award number DMR-08-19762. Use of the Advanced Photon Source was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract no. DE-AC02-06CH11357. M.K. and J.A. gratefully acknowledge support by the NSF Designing Materials to Revolutionize and Engineer our Future program (DMR 1533985). M.K. thanks the Alexander von Humboldt Foundation for a Feodor Lynen Research Fellowship and gratefully acknowledges financial support from the MIT Department of Mechanical Engineering. D.I.S. gratefully acknowledges support by the NSF (DEB-1354831). We thank A. Schwartzman, Y. Zhang, and S. Chen for their technical assistance and E. Belmonte and B. Anseeuw for providing photographs of A. granulata. D.I.S. collected and identified chiton specimens. M.J.C. and X.X. performed synchrotron experiments. M.J.C. and L.L. processed and analyzed data from synchrotron experiments. L.L. performed electron microscopy studies and mechanical tests with data analysis. M.J.C., G.T.E., M.K., and L.L. performed optical measurements and data analysis. M.K. wrote the ray-tracing program. M.J.C and M.K. performed ray-trace simulations. All authors interpreted results. L.L. and M.J.C. prepared figures, tables, and movies and wrote the draft manuscript. C.O. and J.A. supervised the project. All authors revised the manuscript for submission.}, pages = {952-956}, abstract = {Nature provides a multitude of examples of multifunctional structural materials in which trade-offs are imposed by conflicting functional requirements. One such example is the biomineralized armor of the chiton\ Acanthopleura granulata, which incorporates an integrated sensory system that includes hundreds of eyes with aragonite-based lenses. We use optical experiments to demonstrate that these microscopic lenses are able to form images. Light scattering by the polycrystalline lenses is minimized by the use of relatively large, crystallographically aligned grains. Multiscale mechanical testing reveals that as the size, complexity, and functionality of the integrated sensory elements increase, the local mechanical performance of the armor decreases. However,\ A. granulata\ has evolved several strategies to compensate for its mechanical vulnerabilities to form a multipurpose system with co-optimized optical and structural functions.}, doi = {10.1126/science.aad1246}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:27663225}, author = {Li, L. and Connors, M.J. and Kolle, M. and England, G.T. and Speiser, D.I. and Xiao, X. and Aizenberg, J. and Ortiz, C.} } @article {837581, title = {New functional insights into the internal architecture of the laminated anchor spicules of Euplectella aspergillum}, journal = {Proc. Nat. Acad. Sci.}, volume = {112}, year = {2015}, note = {We thank Prof. Huajian Gao for helpful discussions. This work was supported by the National Science Foundation through Materials Research Science and Engineering Centers Program DMR-0520651 at Brown University, Materials Research Science and Engineering Centers Program DMR-1420570 at Harvard University, and the Korean Institute of Machinery and Materials{\textendash}Brown Nano and Micromechanics for Disaster Mitigation and Technological Reliability project.}, pages = {4976-4981}, abstract = {To adapt to a wide range of physically demanding environmental conditions, biological systems have evolved a diverse variety of robust skeletal architectures. One such example,\ Euplectella aspergillum, is a sediment-dwelling marine sponge that is anchored into the sea floor by a flexible holdfast apparatus consisting of thousands of anchor spicules (long, hair-like glassy fibers). Each spicule is covered with recurved barbs and has an internal architecture consisting of a solid core of silica surrounded by an assembly of coaxial silica cylinders, each of which is separated by a thin organic layer. The thickness of each silica cylinder progressively decreases from the spicule{\textquoteright}s core to its periphery, which we hypothesize is an adaptation for redistributing internal stresses, thus increasing the overall strength of each spicule. To evaluate this hypothesis, we created a spicule structural mechanics model, in which we fixed the radii of the silica cylinders such that the force transmitted from the surface barbs to the remainder of the skeletal system was maximized. Compared with measurements of these parameters in the native sponge spicules, our modeling results correlate remarkably well, highlighting the beneficial nature of this elastically heterogeneous lamellar design strategy. The structural principles obtained from this study thus provide potential design insights for the fabrication of high-strength beams for load-bearing applications through the modification of their internal architecture, rather than their external geometry.}, doi = {10.1073/pnas.1415502112}, url = {http://www.pnas.org/content/112/16/4976}, author = {M.A. Monn and J. C. Weaver and T. Zhang and Aizenberg, J. and H. Kesari} } @article {837571, title = {Stability of Surface-Immobilized Lubricant Interfaces under Flow}, journal = {Chem. Mater.}, volume = {27}, year = {2015}, note = {The authors thank Andreas Carlson for helpful advice and Haylea Ledoux for technical assistance. This material is based upon work supported by the Defense Advanced Research Projects Agency Grant N66001-11-1-4180 and Contract HR0011-13-C-0025, as well as by the Office of Naval Research under Award Number N-000014-12-1-0962 to Princeton University. This work was performed in part at the Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Infrastructure Network (NNIN), which is supported by the National Science Foundation under NSF award no. ECS-0335765. CNS is part of Harvard University.}, pages = {1792-1800}, abstract = {The stability and longevity of surface-stabilized lubricant layers is a critical question in their application as low- and nonfouling slippery surface treatments in both industry and medicine. Here, we investigate lubricant loss from surfaces under flow in water using both quantitative analysis and visualization, testing the effects of underlying surface type (nanostructured versus flat), as well as flow rate in the physiologically relevant range, lubricant type, and time. We find lubricant losses on the order of only ng/cm2\ in a closed system, indicating that these interfaces are relatively stable under the flow conditions tested. No notable differences emerged between surface type, flow rate, lubricant type, or time. However, exposure of the lubricant layers to an air/water interface did significantly increase the amount of lubricant removed from the surface, leading to disruption of the layer. These results may help in the development and design of materials using surface-immobilized lubricant interfaces for repellency under flow conditions.}, doi = {10.1021/cm504652g}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:27663227}, author = {Howell, C. and T.L. Vu and C.P. Johnson and Hou, X. and Ahanotu, O. and J. Alvarenga and D.C. Leslie and O. Uzun and A. Waterhouse and Kim, P. and M. Super and Aizenberg, M. and D.E. Ingber and Aizenberg, J.} } @article {837606, title = {Extremely durable biofouling-resistant metallic surfaces based on electrodeposited nanoporous tungstite films on steel}, journal = {Nat. Commun.}, volume = {6}, year = {2015}, note = {

A.B.T., P.K. and J.A. designed the experiments; A.B.T. constructed the samples and measured chemical, mechanical and wetting properties; A.B.T., S.K. and C.H. designed and performed the anti-biofouling experiments; O.A. discussed and analysed the anti- biofouling data and model; all authors contributed to the interpretation, conception and presentation of the data and wrote the article; J.A. supervised the research.

}, pages = {8649}, abstract = {Formation of unwanted deposits on steels during their interaction with liquids is an inherent problem that often leads to corrosion, biofouling and results in reduction in durability and function. Here we report a new route to form anti-fouling steel surfaces by electrodeposition of nanoporous tungsten oxide (TO) films. TO-modified steels are as mechanically durable as bare steel and highly tolerant to compressive and tensile stresses due to chemical bonding to the substrate and island-like morphology. When inherently superhydrophilic TO coatings are converted to superhydrophobic, they remain non-wetting even after impingement with yttria-stabilized-zirconia particles, or exposure to ultraviolet light and extreme temperatures. Upon lubrication, these surfaces display omniphobicity against highly contaminating media retaining hitherto unseen mechanical durability. To illustrate the applicability of such a durable coating in biofouling conditions, we modified naval construction steels and surgical instruments and demonstrated significantly reduced marine algal film adhesion,\ Escherichia coli\ attachment and blood staining.}, doi = {10.1038/ncomms9649}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:23993627}, author = {Tesler, A.B. and Kim, P. and Kolle, S. and Howell, C. and Ahanotu, O. and Aizenberg, J.} } @article {913076, title = {Slippery Liquid-Infused Porous Surfaces}, journal = {The Journal of Ocean Technology}, volume = {9}, year = {2014}, month = {Winter 2014}, pages = {113-114}, abstract = {

Marine biofouling, the process of accumulation of microorganisms, plants, algae and animals on submerged surfaces, is an age-old problem associated with any maritime activity affecting commercial and recreational shipping activities, naval operations, aquaculture facilities and marine renewable energy structures alike. The adverse effects of marine biofouling include the increase of drag on ship hulls, damage to ships and maritime equipment such as corrosion, the spread of diseases in aquaculture and the distribution of invasive species causing extensive damage to coastal ecosystems and the benefits derived from them. An estimated global annual total of $60 billion in fuel cost alone can be saved by the application of marine antifouling coatings, making the treatment of marine biofouling a necessity not an option.

}, author = {Aizenberg, Joanna} } @article {837536, title = {Bioinspired micrograting arrays mimicking the reverse color diffraction elements evolved by the butterfly Pierella luna}, journal = {Proc. Nat. Acad. Sci.}, volume = {111}, year = {2014}, note = {This work was supported by the US Air Force Office of Scientific Research Multidisciplinary University Research Initiative under Award FA9550-09-1-0669-DOD35CAP. M. Kolle acknowledges financial support from the Alexander von Humboldt Foundation in the form of a Feodor-Lynen Postdoctoral Research Fellowship.}, pages = {15630{\textendash}15634}, abstract = {

Recently, diffraction elements that reverse the color sequence normally observed in planar diffraction gratings have been found in the wing scales of the butterfly Pierella luna. Here, we describe the creation of an artificial photonic material mimicking this re- verse color-order diffraction effect. The bioinspired system con- sists of ordered arrays of vertically oriented microdiffraction gratings. We present a detailed analysis and modeling of the cou- pling of diffraction resulting from individual structural compo- nents and demonstrate its strong dependence on the orientation of the individual miniature gratings. This photonic material could provide a basis for novel developments in biosensing, anticoun- terfeiting, and efficient light management in photovoltaic systems and light-emitting diodes.

}, doi = {10.1073/pnas.1412240111}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:27417440}, author = {G. England and Kolle, M. and Kim, P. and Khan, M. and P. Munoz and E. Mazur and Aizenberg, J.} } @article {837541, title = {A bioinspired omniphobic surface coating on medical devices prevents thrombosis and biofouling}, journal = {Nature Biotechnology}, volume = {32}, year = {2014}, note = {This work was supported by Defense Advanced Research Projects Agency grant N66001-11-1-4180 and contract HR0011-13-C-0025, and the Wyss Institute for Biologically Inspired Engineering at Harvard University. We thank D. Super, R. Cooper, E. Murray and J. Lee for phlebotomy, T. Ferrante for assistance with fluorescence microscopy, H. Kozakewich for assistance with histology evaluation and O. Ahanotu for assistance in preparing surfaces. Scanning electron microscopy and X-ray photoelectron spectroscopy were conducted at the Center for Nanoscale Systems at Harvard University, a member of the National Nanotechnology Infrastructure Network, which is supported by the National Science Foundation (ECS-0335765).}, pages = {1134-1140}, abstract = {

Thrombosis and biofouling of extracorporeal circuits and indwelling medical devices cause significant morbidity and mortality worldwide. We apply a bioinspired, omniphobic coating to tubing and catheters and show that it completely repels blood and suppresses biofilm formation. The coating is a covalently tethered, flexible molecular layer of perfluorocarbon, which holds a thin liquid film of medical-grade perfluorocarbon on the surface. This coating prevents fibrin attachment, reduces platelet adhesion and activation, suppresses biofilm formation and is stable under blood flow in vitro. Surface-coated medical-grade tubing and catheters, assembled into arteriovenous shunts and implanted in pigs, remain patent for at least 8 h without anticoagulation. This surface-coating technology could reduce the use of anticoagulants in patients and help to prevent thrombotic occlusion and biofouling of medical devices.

}, doi = {10.1038/nbt.3020}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:34298865}, author = {D.C. Leslie and A. Waterhouse and J.B. Berthet and T.M. Valentin and A.L. Watters and A. Jain and Kim, P. and B.D. Hatton and A. Nedder and K. Donovan and E.H. Super and Howell, C. and C.P. Johnson and T.L. Vu and D.E. Bolgen and S. Rifai and A.R. Hansen and Aizenberg, M. and M. Super and Aizenberg, J. and D.E. Ingber} } @article {837496, title = {Developmentally-Inspired Shrink-Wrap Polymers for Mechanical Induction of Tissue Differentiation}, journal = {Adv. Mater.}, volume = {26}, year = {2014}, note = {This work was conducted with support by grants from the NIH Common Fund (RL1DE019023 to D.E.I.), the Wyss Institute for Biologically Inspired Engineering at Harvard University, and partially from the DOE BES (DE-SC0005247 to J.A.). We would like to thank E. Jiang and M. Kowalski for their technical assistance and T. Ferrante for assistance in imaging.}, pages = {3253-3257}, abstract = {A biologically inspired thermoresponsive polymer\ has been developed that mechanically induces tooth differentiation in vitro and in vivo by promoting mesenchymal cell compaction as seen in each pore of the scaffold. This normally occurs during the physiological mesenchymal condensation response that triggers tooth formation in the embryo.}, doi = {10.1002/adma.201304995}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201304995}, author = {B. Hashmi and L. D. Zarzar and T. Mammoto and A. Jiang and Aizenberg, J. and D.E. Ingber} } @article {837521, title = {Directional Wetting in Anisotropic Inverse Opals}, journal = {Langmuir}, volume = {30}, year = {2014}, note = {K.R.P. acknowledges support from a National Science Foundation Graduate Research Fellowship and a National Defense Science and Engineering Graduate fellowship from the Department of Defense. N.V. acknowledges funding from the Leopoldina Fellowship Program. C.C.P. acknowledges the support of an Edward, Frances and Shirley B. Daniels and Wyss Fellowship while at the Radcliffe Institute for Advanced Study, 2012-2013. The authors thank A. V. Shneidman for helpful discussions. This work was funded with support from the Air Force Office of Scientific Research (AFOSR) under Award FA9550-09-0669-DOD35CAP, and it was performed in part at the Center for Nanoscale Systems (CNS) at Harvard University.}, pages = {7615-7620}, abstract = {

Porous materials display interesting transport phenomena due to restricted motion of fluids within the nano- to microscale voids. Here, we investigate how liquid wetting in highly ordered inverse opals is affected by anisotropy in pore geometry. We compare samples with different degrees of pore asphericity and find different wetting patterns depending on the pore shape. Highly anisotropic structures are infiltrated more easily than their isotropic counterparts. Further, the wetting of anisotropic inverse opals is directional, with liquids filling from the side more easily. This effect is supported by percolation simulations as well as direct observations of wetting using time-resolved optical microscopy.

}, doi = {10.1021/la5015253}, url = {https://pubs.acs.org/doi/abs/10.1021/la5015253}, author = {Phillips, K.R. and Vogel, N. and Burgess, I.B. and C.C. Perry and Aizenberg, J.} } @article {837531, title = {Dynamic daylight control system implementing thin cast arrays of polydimethylsiloxane-based millimeter-scale transparent louvers}, journal = {Building and Environment}, volume = {82}, year = {2014}, note = {This research is supported by the Wyss Institute for Biologically Inspired Engineering. The project was developed as part of the ongoing interdisciplinary collaboration between members of the Harvard University Graduate School of Design and the Adaptive Material Technologies platform at the Wyss Institute. The authors thank Professor Holly Samuelson for the thorough review of this paper; Allen Sayegh for his contributions throughout; Kevin Hinz and Jeonghyun Kim for fabricating the shoebox testing setup; James Weaver for 3D printing support; and Thomas Blough for the technical input during the early phase of the research. Timor Doganwas instrumental in the development of the initial concept.}, pages = {87-96}, abstract = {

The deep building layouts typical in the U.S. have led to a nearly complete reliance on artificial lighting in standard office buildings. The development of daylight control systems that maximize the penetration and optimize the distribution of natural daylight in buildings has the potential for saving a significant portion of the energy consumed by artificial lighting, but existing systems are either static, costly, or obstruct views towards the outside. We report the Dynamic Daylight Control System (DDCS) that in- tegrates a thin cast transparent polydimethylsiloxane (PDMS)-based deformable array of louvers and waveguides within a millimeter-scale fluidic channel system. This system can be dynamically tuned to the different climates and sun positions to control daylight quality and distribution in the interior space. The series of qualitative and quantitative tests confirmed that DDCS exceeds conventional double glazing system in terms of reducing glare near the window and distributing light to the rear of the space. The system can also be converted to a visually transparent or a translucent glazing by filling the channels with an appropriate fluid. DDCS can be integrated or retrofitted to conventional glazing systems and allow for diffusivity and transmittance control.

}, doi = {10.1016/j.buildenv.2014.07.016}, url = {https://www.sciencedirect.com/science/article/pii/S0360132314002406}, author = {D. Park and Kim, P. and J. Alvarenga and K. Jin and Aizenberg, J. and M. Bechtold} } @article {837516, title = {The Elemental Composition of Demospongiae from the Red Sea, Gulf of Aqaba}, journal = {PLoS ONE}, volume = {9}, year = {2014}, note = {This research was funded by US-Israel Binational Science Foundation grant No. 2003340 (http://www.bsf.org.il/BSFPublic/Default.aspx). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.}, pages = {e95775}, abstract = {

Trace elements are vital for the growth and development of all organisms. Little is known about the elemental content and trace metal biology of Red Sea demosponges. This study establishes an initial database of sponge elemental content. It provides the necessary foundation for further research of the mechanisms used by sponges to regulate the uptake, accumulation, and storage of metals. The metal content of 16 common sponge species was determined using ICP measurements. A combination of statistical methods was used to determine the correlations between the metals and detect species with significantly high or low concentrations of these metals. Bioaccumulation factors were calculated to compare sponge metal content to local sediment. Theonella swinhoei contained an extremely high concentration of arsenic and barium, much higher (at least 200 times) than all other species and local sediment. Hyrtios erecta had significantly higher concentration of Al, Cr, Fe, Mn, Ti and V than all other species. This is due to sediment accumulation and inclusion in the skeleton fibers of this sponge species. Suberites clavatus was found to contain significantly higher concentration of Cd, Co, Ni and Zn than all other species and local sediment, indicating active accumulation of these metals. It also has the second highest Fe concentration, but without the comparably high concentrations of Al, Mn and Ti that are evident in H. erecta and in local sediment. These differences indicate active uptake and accumulation of Fe in S. clavatus, this was also noted in Niphates rowi. A significantly higher B concentration was found in Crella cyatophora compared to all other species. These results indicate specific roles of trace elements in certain sponge species that deserve further analysis. They also serve as a baseline to monitor the effects of anthropogenic disturbances on Eilat{\textquoteright}s coral reefs.

}, doi = {10.1371/journal.pone.0095775}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:12152900}, author = {B. Mayzel and Aizenberg, J. and M. Ilan} } @article {837486, title = {Fabrics coated with lubricated nanostructures display robust omniphobicity}, journal = {Nanotechnology}, volume = {25}, year = {2014}, note = {

We thank Tom Blough and Jack Alvarenga for their help with the experimental setup. The work was supported partially by the Advanced Research Projects Agency-Energy (ARPA-E), US Department of Energy, under Award Number DE-AR0000326 and the Wyss Institute for Biologically Inspired Engineering at Harvard University. We acknowledge the use of the facilities at the Harvard Center for Nanoscale Systems supported by the NSF under award ECS-0335765.

}, pages = {014019}, abstract = {

The development of a stain-resistant and pressure-stable textile is desirable for consumer and industrial applications alike, yet it remains a challenge that current technologies have been unable to fully address. Traditional superhydrophobic surfaces, inspired by the lotus plant, are characterized by two main components: hydrophobic chemical functionalization and surface roughness. While this approach produces water-resistant surfaces, these materials have critical weaknesses that hinder their practical utility, in particular as robust stain-free fabrics. For example, traditional superhydrophobic surfaces fail (i.e., become stained) when exposed to low-surface-tension liquids, under pressure when impacted by a high-velocity stream of water (e.g., rain), and when exposed to physical forces such as abrasion and twisting. We have recently introduced slippery lubricant-infused porous surfaces (SLIPS), a self-healing, pressure-tolerant and omniphobic surface, to address these issues. Herein we present the rational design and optimization of nanostructured lubricant-infused fabrics and demonstrate markedly improved performance over traditional superhydrophobic textile treatments: SLIPS-functionalized cotton and polyester fabrics exhibit decreased contact angle hysteresis and sliding angles, omni-repellent properties against various fluids including polar and nonpolar liquids, pressure tolerance and mechanical robustness, all of which are not readily achievable with the state-of-the-art superhydrophobic coatings.

}, doi = {10.1088/0957-4484/25/1/014019}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:27657492}, author = {C. Shillingford and MacCallum, N. and Wong, T.S. and Kim, P. and Aizenberg, J.} } @article {837506, title = {Fluorogel Elastomers with Tunable Transparency, Elasticity, Shape- Memory, and Antifouling Properties}, journal = {Angew. Chem. Int. Ed}, volume = {53}, year = {2014}, note = {We thank Dr. M. Aizenberg for discussions. This work was supported by the Advanced Research Projects Agency-Energy (ARPA-E) under award number DE-AR0000326.}, pages = {4418-4422}, abstract = {

Omniphobic fluorogel elastomers were prepared by photocuring perfluorinated acrylates and a perfluoropolyether crosslinker. By tuning either the chemical composition or the temperature that control the crystallinity of the resulting polymer chains, a broad range of optical and mechanical properties of the fluorogel can be achieved. After infusing with fluorinated lubricants, the fluorogels showed excellent resist- ance to wetting by various liquids and anti-biofouling behavior, while maintaining cytocompatiblity.

}, doi = {10.1002/anie.201310385}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:27662698}, author = {X. Yao and S. Dunn and Kim, P. and M. Duffy and J. Alvarenga and Aizenberg, J.} } @article {837551, title = {Hierarchical structural control of visual properties in self-assembled photonic-plasmonic pigments}, journal = {Opt. Express}, volume = {22}, year = {2014}, note = {We thank Dr. Caitlin Howell, Derek Cranshaw and Charlie Payne for helpful discussions. The work was supported by the US AFOSR under award number FA9550-09-1-0669-DOD35CAP and in part by the BASF SE. Template microfabrication and electron microscopy of the photonic bricks were performed at the Center for Nanoscale Systems (CNS) at Harvard University, a member of the National Nanotechnology Infrastructure Network (NNIN), which is supported by the NSF under award number ECS-0335765. M.K. acknowledges support from a Feodor Lynen postdoctoral research fellowship from the Alexander von Humboldt Foundation. I.B.B. acknowledges support from a Banting Postdoctoral Fellowship funded by the Natural Sciences and Engineering Research Council of Canada (NSERC). K.R.P. acknowledges support from a DoD National Defense Science and Engineering Graduate Fellowship. N.V. acknowledges support from the Leopoldina Fellowship. T.S. acknowledges support from the Weizmann Institute of Science {\textendash} National Postdoctoral Award Program for Advancing Women in Science.}, pages = {27750-27768}, abstract = {

We present a simple one-pot co-assembly method for the synthesis of hierarchically structured pigment particles consisting of silica inverse-opal bricks that are doped with plasmonic absorbers. We study the interplay between the plasmonic and photonic resonances and their effect on the visual appearance of macroscopic collections of photonic bricks that are distributed in randomized orientations. Manipulating the pore geometry tunes the wavelength- and angle-dependence of the scattering profile, which can be engineered to produce angle-dependent Bragg resonances that can either enhance or contrast with the color produced by the plasmonic absorber. By controlling the overall dimensions of the photonic bricks and their aspect ratios, their preferential alignment can either be encouraged or suppressed. This causes the Bragg resonance to appear either as uniform color travel in the former case or as sparse iridescent sparkle in the latter case. By manipulating the surface chemistry of these photonic bricks, which introduces a fourth length-scale (molecular) of independent tuning into our design, we can further engineer interactions between liquids and the pores. This allows the structural color to be maintained in oil-based formulations, and enables the creation of dynamic liquid-responsive images from the pigment.

}, doi = {10.1364/OE.22.027750}, url = {https://doi.org/10.1364/OE.22.027750}, author = {N. Koay and I. Burgess and T. Kay and B. Nerger and M. Miles-Rossouw and Shirman, T. and T. Vu and G. England and K. Phillips and S. Utech and Vogel, N. and Kolle, M. and and J. Aizenberg} } @article {837526, title = {Lubricant-infused Nanoparticulate Coatings Assembled by Layer-by-layer Deposition}, journal = {Adv. Funct. Mater.}, volume = {24}, year = {2014}, note = {N.V. acknowledges support from the Leopoldina Fellowship Programme. S.S. acknowledges support from the Natural Sciences and Engineering Research Council of Canada. The work was supported by the ARPA-E under award number DE-AR0000326 (fabrication and surface properties) and by the AFOSR under award number FA9550{\textendash}09{\textendash}0669-DOD35CAP (optical properties). This work was performed in part at the Harvard Center for Nanoscale Systems (CNS) supported by the NSF under award number ECS-0335765.}, pages = {6658-6667}, abstract = {

Omniphobic coatings are designed to repel a wide range of liquids without leaving stains on the surface. A practical coating should exhibit stable repel- lency, show no interference with color or transparency of the underlying substrate and, ideally, be deposited in a simple process on arbitrarily shaped surfaces. We use layer-by-layer (LbL) deposition of negatively charged silica nanoparticles and positively charged polyelectrolytes to create nanoscale sur- face structures that are further surface-functionalized with fluorinated silanes and infiltrated with fluorinated oil, forming a smooth, highly repellent coating on surfaces of different materials and shapes. We show that four or more
LbL cycles introduce sufficient surface roughness to effectively immobilize the lubricant into the nanoporous coating and provide a stable liquid inter- face that repels water, low-surface-tension liquids and complex fluids. The absence of hierarchical structures and the small size of the silica nanoparti- cles enables complete transparency of the coating, with light transmittance exceeding that of normal glass. The coating is mechanically robust, maintains its repellency after exposure to continuous flow for several days and prevents adsorption of streptavidin as a model protein. The LbL process is conceptu- ally simple, of low cost, environmentally benign, scalable, automatable and therefore may present an efficient synthetic route to non-fouling materials.

}, doi = {10.1002/adfm.201401289}, author = {Sunny, S. and Vogel, N. and Howell, C. and T.L. Vu and Aizenberg, J.} } @article {837546, title = {Mobile Interfaces: Liquids as a Perfect Structural Material for Multifunctional, Antifouling Surfaces}, journal = {Chem. Mater.}, volume = {26}, year = {2014}, note = {This work was supported by the ONR MURI Award Number N00014-12-1-0875 and by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0000326.}, pages = {698-708}, abstract = {

Life creates some of its most robust, extreme surface materials not from solids but from liquids: a purely liquid interface, stabilized by underlying nanotexture, makes carnivorous plant leaves ultraslippery, the eye optically perfect and dirt-resistant, our knees lubricated and pressure-tolerant, and insect feet reversibly adhesive and shape-adaptive. Novel liquid surfaces based on this idea have recently been shown to display unprecedented omniphobic, self-healing, anti-ice, antifouling, optical, and adaptive properties. In this Perspective, we present a framework and a path forward for developing and designing such liquid surfaces into sophisticated, versatile multifunctional materials. Drawing on concepts from solid materials design and fluid dynamics, we outline how the continuous dynamics, responsiveness, and multiscale patternability of a liquid surface layer can be harnessed to create a wide range of unique, active interfacial functions -able to operate in harsh, changing environments- not achievable with static solids. We discuss how, in partnership with the underlying substrate, the liquid surface can be programmed to adaptively and reversibly reconfigure from a defect-free, molecularly smooth, transparent interface through a range of finely tuned liquid topographies in response to environmental stimuli. With nearly unlimited design possibilities and unmatched interfacial properties, liquid materials -as long-term stable interfaces yet in their fully liquid state- may potentially transform surface design everywhere from medicine to architecture to energy infrastructure.

}, doi = {10.1021/cm402364d}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:27662700}, author = {Grinthal, A. and Aizenberg, J.} } @article {837471, title = {Photo-tuning of Highly Selective Wetting in Inverse Opals}, journal = {Soft Matter}, volume = {10}, year = {2014}, note = {This work was supported by the Air Force Office of Scientific Research under Award FA9550-09-1-0669-DOD35CAP (Harvard), the Natural Sciences and Engineering Research Council of Canada and Canadian Foundation for Innovation (McGill). AGH would like to acknowledge FQRNT for a B2 doctoral scholarship.}, pages = {1325-1328}, abstract = {

Crack-free inverse opals exhibit a sharply defined threshold wettability for infiltration that has enabled their use as colourimetric indicators for liquid identification. Here we demonstrate direct and continuous photo-tuning of this wetting threshold in inverse opals whose surfaces are function- alized with a polymer doped with azobenzene chromophores.

}, doi = {10.1039/C3SM52684D}, url = {http://pubs.rsc.org/en/content/articlelanding/2014/sm/c3sm52684d$\#$!divAbstract}, author = {T.A. Singleton and Burgess, I.B. and B.A. Nerger and A. Goulet-Hanssens and N. Koay and C.J. Barrett and Aizenberg, J.} } @article {837501, title = {Reconfigurable soft matter}, journal = {Soft Matter}, volume = {10}, year = {2014}, note = {We thank the authors for their time and effort in contributing to this issue. We are particularly grateful to the staff of Soft Matter for all their help in this endeavor}, pages = {1244-1245}, doi = {10.1039/C4SM90006E}, url = {http://pubs.rsc.org/en/content/articlelanding/2014/sm/c4sm90006e$\#$!divAbstract}, author = {Balazs, A.C. and Aizenberg, J.} } @article {837511, title = {Self-Replenishing Vascularized Fouling-Release Surfaces}, journal = {ACS Appl. Mater. Interfaces}, volume = {6}, year = {2014}, note = {The authors thank Ron Parsons and Joel Butler at Solix Biosystems for providing the N. oculata cultures, and John Skutnik for the D. salina cultures. The authors also thank Shira Lehmann, Bobak Mosadegh and A. Arias Palomo for technical assistance, Isa DuMond for culture assistance, and Ian Burgess for editorial assistance. The leaf vasculature used for the 3D molds was taken by Jon Sullivan (PDPhoto.org) and obtained from the public domain at Wikimedia Commons. The information, data, or work presented herein was funded in part by the Office of Naval Research under award no. N00014- 11-1-0641 and by the Advanced Research Projects Agency-Energy (ARPA-E) under award no. DE-AR0000326.}, pages = {13299-13307}, abstract = {

Inspired by the long-term effectiveness of living
antifouling materials, we have developed a method for the self-
replenishment of synthetic biofouling-release surfaces. These
surfaces are created by either molding or directly embedding
3D vascular systems into polydimethylsiloxane (PDMS) and
filling them with a silicone oil to generate a nontoxic oil-
infused material. When replenished with silicone oil from an
outside source, these materials are capable of self-lubrication
and continuous renewal of the interfacial fouling-release layer.
Under accelerated lubricant loss conditions, fully infused vascularized samples retained significantly more lubricant than equivalent nonvascularized controls. Tests of lubricant-infused PDMS in static cultures of the infectious bacteria Staphylococcus aureus and Escherichia coli as well as the green microalgae Botryococcus braunii, Chlamydomonas reinhardtii, Dunaliella salina, and Nannochloropsis oculata showed a significant reduction in biofilm adhesion compared to PDMS and glass controls containing no lubricant. Further experiments on vascularized versus nonvascularized samples that had been subjected to accelerated lubricant evaporation conditions for up to 48 h showed significantly less biofilm adherence on the vascularized surfaces. These results demonstrate the ability of an embedded lubricant-filled vascular network to improve the longevity of fouling-release surfaces.

}, doi = {10.1021/am503150y}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:27738666}, author = {Howell, C. and T.L. Vu and Lin, J.J. and Kolle, S. and N. Juthani and E. Watson and J. C. Weaver and J. Alvarenga and Aizenberg, J.} } @article {837481, title = {Stimuli-Responsive Chemomechanical Actuation: A Hybrid Materials Approach}, journal = {Acc. Chem. Res.}, volume = {47}, year = {2014}, note = {We thank Dr. Alison Grinthal and Dr. Ximin He for their helpful discussions and comments during the preparation of this manu- script. The work was supported by the DOE under Award DE-SC0005247 and by NSF under Award CMMI-1124839.}, pages = {530-539}, abstract = {

Dynamic materials that can sense changes in their surroundings and functionally respond by altering many of their physical characteristics are primed to be integral components of future {\textquotedblleft}smart{\textquotedblright} technologies. A fundamental reason for the adaptability of biological organisms is their innate ability to convert environmental or chemical cues into mechanical motion and reconfiguration on both the molecular and macroscale. However, design and engineering of robust chemomechanical behavior in artificial materials has proven a challenge. Such systems can be quite complex and often require intricate coordination between both chemical and mechanical inputs and outputs, as well as the combination of multiple materials working cooperatively to achieve the proper functionality. It is critical to not only understand the fundamental behaviors of existing dynamic chemo- mechanical systems but also apply that knowledge and explore new avenues for design of novel materials platforms that could provide a basis for future adaptive technologies.
In this Account, we explore the chemomechanical behavior, properties, and applications of hybrid-material surfaces consisting of environmentally sensitive hydrogels integrated within arrays of high-aspect-ratio nano- or microstructures. This bio-inspired approach, in which the volume-changing hydrogel acts as the {\textquotedblleft}muscle{\textquotedblright} that reversibly actuates the microstructured {\textquotedblleft}bones{\textquotedblright}, is highly tunable and customizable. Although straightforward in concept, the combination of just these two materials (structures and hydrogel) has given rise to a far more complex set of actuation mechanisms and behaviors. Variations in how the hydrogel is physically integrated within the structure array provide the basis for three fundamental mechanisms of actuation, each with its own set of responsive properties and chemomechanical behavior. Further control over how the chemical stimulus is applied to the surface, such as with microfluidics, allows for generation of more precise and varied patterns of actuation. We also discuss the possible applications of these hybrid surfaces for chemomechanical manipulation of reactions, including the generation of chemomechanical feedback loops. Comparing and contrasting these many approaches and techniques, we aim to put into perspective their highly tunable and diverse capabilities but also their future challenges and impacts.

}, doi = {10.1021/ar4001923}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:27663228}, author = {L. D. Zarzar and Aizenberg, J.} } @article {837466, title = {Three-Phase Co-Assembly: In-situ Incorporation of Nanoparticles into Tunable, Highly-Ordered, Porous Silica FIlms}, journal = {ACS Photonics}, volume = {1}, year = {2014}, note = {This work was supported by the AFOSR under Award $\#$ 32 33 34 35 FA9550-09-1-0669-DOD35CAP. L.M. acknowledges fel- lowship support from the Department of Homeland Securi- ty (DHS). M.K. acknowledges funding from the Alexander von Humboldt-Foundation.}, pages = {53-60}, abstract = {

We present a reproducible, one-pot colloidal co-assembly approach that results in large-scale, highly ordered porous silica films with embedded, uniformly distributed, accessible gold nanoparticles. The unique coloration of these inverse opal films combines iridescence with plasmonic effects. The coupled optical properties are easily tunable either by changing the concentration of added nanoparticles to the solution before assembly or by localized growth of the embedded Au nanoparticles upon exposure to tetrachloroauric acid solution, after colloidal template removal. The presence of the selectively absorbing particles furthermore enhances the hue and saturation of the inverse opals{\textquoteright} color by suppressing incoherent diffuse scattering. The composition and optical properties of these films are demonstrated to be locally tunable using selective functionalization of the doped opals.

}, doi = {10.1021/ph400067z}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:33204051}, author = {Vasquez, Y. and Kolle, M. and L. Mishchenko and B.D. Hatton and Aizenberg, J.} } @article {837491, title = {Tunable Anisotropy in Inverse Opals and Emerging Optical Properties}, journal = {Chem. Mater.}, volume = {26}, year = {2014}, note = {■ ACKNOWLEDGMENTS K.R.P. acknowledges support from a National Science Foundation Graduate Research Fellowship and a National Defense Science and Engineering Graduate Fellowship from the Department of Defense. N.V. acknowledges funding from the Leopoldina Fellowship Program. M.K. acknowledges support from the Alexander von Humboldt Foundation. C.C.P. acknowledges the support of an Edward, Frances and Shirley B. Daniels and Wyss Fellowship while at the Radcliffe Institute for Advanced Study (2012-2013). The authors thank Dr. Ian Burgess and Dr. Caitlin Howell for helpful discussions and Grant England and Jack Alvarenga for help with the angular reflectance and infrared instruments, respectively. This work was funded with support from the Air Force Office of Scientific Research (AFOSR) via Grant FA9550-09-0669-DOD35CAP. This work was performed in part at the Center for Nanoscale Systems (CNS) at Harvard University, which is supported by National Science Foundation Grant ECS-0335765.}, pages = {1622-1628}, abstract = {

Using self-assembly, nanoscale materials can be fabricated from the bottom up. Opals and inverse opals are examples of self-assembled nanomaterials made from crystallizing colloidal particles. As self-assembly requires a high level of control, it is challenging to use building blocks with anisotropic geometry to form complex opals, which limits the possible structures. Typically, spherical colloids are employed as building blocks, leading to symmetric, isotropic superstructures. However, a significantly richer palette of directionally dependent properties are expected if less symmetric, anisotropic structures can be created, especially originating from the assembly of regular, spherical particles. Here we show a simple method for introducing anisotropy into inverse opals by subjecting them to a post-assembly thermal treatment that results in directional shrinkage of the silica matrix caused by condensation of partially hydrated sol-gel silica structures. In this way, we can tailor the shape of the pores, and the anisotropy of the final inverse opal preserves the order and uniformity of the self-assembled structure. Further, we prevent the need to synthesize complex oval-shaped particles and crystallize them into such target geometries. Detailed X-ray photoelectron spectroscopy and infrared spectroscopy studies clearly identify increasing degrees of sol-gel condensation in confinement as a mechanism for the structure change. A computer simulation of structure changes resulting from the condensation-induced shrinkage further confirmed this mechanism. As an example of property changes induced by the introduction of anisotropy, we characterized the optical spectra of the anisotropic inverse opals and found that the optical properties can be controlled in a precise way using calcination temperature.

}, doi = {10.1021/cm403812y}, url = {https://pubs.acs.org/doi/abs/10.1021/cm403812y}, author = {Phillips, K.R. and Vogel, N. and Hu, Y. and Kolle, M. and C.C. Perry and Aizenberg, J.} } @article {968926, title = {Wetting in Color: From photonic fingerprinting of liquids to optical control of liquid percolation}, journal = {Proc. of SPIE}, volume = {8632}, year = {2013}, pages = {863201}, abstract = {

We provide an overview of our recent advances in the manipulation of wetting in inverse-opal photonic crystals. Exploiting photonic crystals with spatially patterned surface chemistry to confine the infiltration of fluids to liquidspecific spatial patterns, we developed a highly selective scheme for colorimetry, where organic liquids are distinguished based on wetting. The high selectivity of wetting, upon-which the sensitivity of the response relies, and the bright iridescent color, which disappears when the pores are filled with liquid, are both a result of the highly symmetric pore structure of our inverse-opal films. The application of horizontally or vertically orientated gradients in the surface chemistry allows a unique response to be tailored to specific liquids. While the generic nature of wetting makes our approach to colorimetry suitable for applications in liquid authentication or identification across a broad range of industries, it also ensures chemical non-specificity. However, we show that chemical specificity can be achieved combinatorially using an array of indicators that each exploits different chemical gradients to cover the same dynamic range of response. Finally, incorporating a photo-responsive polyelectrolyte surface layer into the pores, we are able to dynamically and continuously photo-tune the wetting response, even while the film is immersed in liquid. This in situ optical control of liquid percolation in our photonic-crystal films may also provide an error-free means to tailor indicator response, naturally compensating for batch-to-batch variability in the pore geometry.

}, url = {https://www.spiedigitallibrary.org/conference-proceedings-of-spie/8632/1/Wetting-in-color--from-photonic-fingerprinting-of-liquids-to/10.1117/12.2013366.short?SSO=1}, author = {Burgess, I.B. and B.A. Nerger and K.P. Raymond and A. Goulet-Hanssens and T.A. Singleton and M.H. Kinney and Shneidman, A.V. and N. Koay and C.J. Barrett and Loncar, M. and Aizenberg, J.} } @article {968881, title = {Interfacial materials with special wettability}, journal = {MRS Bulletin}, volume = {38}, year = {2013}, pages = {366-371}, abstract = {

Various life forms in nature display a high level of adaptability to their environments through the use of sophisticated material interfaces. This is exemplifi ed by numerous biological systems, such as the self-cleaning of lotus leaves, the water-walking abilities of water striders and spiders, the ultra-slipperiness of pitcher plants, the directional liquid adhesion of butterfl y wings, and the water collection capabilities of beetles, spider webs, and cacti. The versatile interactions of these natural surfaces with fl uids, or special wettability, are enabled by their unique micro/nanoscale surface structures and intrinsic material properties. Many of these biological designs and principles have inspired new classes of functional interfacial materials, which have remarkable potential to solve some of the engineering challenges for industrial and biomedical applications. In this article, we provide a snapshot of the state of the art of biologically inspired materials with special wettability, and discuss some promising future directions for the field.

}, url = {https://www.cambridge.org/core/journals/mrs-bulletin/article/interfacial-materials-with-special-wettability/D0E7D6EE5FC8930798D0206C87492E8E}, author = {T.-S. Wong and Sun, T. and Feng, L. and Aizenberg, J.} } @article {968851, title = {New Materials through Bioinspiration and Nanoscience}, journal = {Adv. Funct. Mater.}, volume = {23}, year = {2013}, pages = {4398-4399}, url = {https://doi.org/10.1002/adfm.201302690}, author = {Aizenberg, J. and P. Fratzl} } @article {837411, title = {Adaptive all the way down: Building responsive materials from hierarchies of chemomechanical feedback}, journal = {Chem. Soc. Rev.}, volume = {42}, year = {2013}, note = {This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences Tutorial Review Chem Soc Rev Downloaded by Harvard University on 26/04/2013 22:18:02. Published on 26 April 2013 on http://pubs.rsc.org | doi:10.1039/C3CS60045A View Article Online This journal is c The Royal Society of Chemistry 2013 Chem. Soc. Rev. and Engineering under award number DE-SC0005247 (design of adaptive materials); by the U.S. Air Force Office of Scientific Research Multidisciplinary University Research Initiative under award number FA9550-09-1-0669-DOD35CAP (dynamic optical structures); and by the U.S. National Science Foundation under award number CMMI-1124839 (chemo-mechanical feedback systems). We gratefully acknowledge Dr Michael DeVolder for providing the image of hydrogel-infiltrated carbon nanotubes.}, pages = {7072-7085}, abstract = {A living organism is a bundle of dynamic, integrated adaptive processes: not only does it continuously respond to constant changes in temperature, sunlight,\ nutrients, and other features of its environment, but it does so by coordinating hierarchies of feedback among cells, tissues, organs, and networks all continuously adapting to each other. At the root of it all is one of the most fundamental adaptive processes: the constant tug of war between chemistry and mechanics that interweaves chemical signals with endless reconfigurations of\ macromolecules, fibers, meshworks, and membranes. In this tutorial we explore how such chemomechanical feedback {\textendash} as an inherently dynamic, iterative process connecting size and time scales {\textendash} can and has been similarly evoked in synthetic materials to produce a fascinating diversity of complex multiscale responsive behaviors. We discuss how chemical kinetics and architecture can be designed to generate stimulus-induced 3D spatiotemporal waves and topographic patterns within a single bulk material, and how feedback between interior dynamics and surface-wide instabilities can further generate higher order buckling and wrinkling patterns. Building on these phenomena, we show how yet higher levels of feedback and spatiotemporal complexity can be programmed into hybrid materials, and how these mechanisms allow hybrid materials to be further integrated into multicompartmental systems capable of hierarchical chemo-mechano-chemical feedback responses. These responses no doubt represent only a small sample of the chemomechanical feedback behaviors waiting to be discovered in synthetic materials, and enable us to envision nearly limitless possibilities for designing multiresponsive, multifunctional, self-adapting materials and systems.}, doi = {10.1039/C3CS60045A}, url = {http://pubs.rsc.org/en/Content/ArticleLanding/2013/CS/c3cs60045a$\#$!divAbstract}, author = {Grinthal, A. and Aizenberg, J.} } @article {837401, title = {Adaptive fluid-infused porous films with tunable transparency and wettability}, journal = {Nature Materials}, volume = {12}, year = {2013}, note = {The work was supported by the AFOSR MURI award FA9550-09-1-0669-DOD35CAP (optical properties) and the ONR MURI award N00014-12-1-0875 (wetting properties). We thank T. Blough for the help in stretcher design and fabrication. We also thank M. Kolle and J. Alvarenga for the help with the optical test. We acknowledge the use of the facilities at the Harvard Center for Nanoscale Systems supported by the NSF under award ECS-0335765.}, pages = {529-534}, abstract = {Materials that adapt dynamically to environmental changes are currently limited to two-state switching of single properties, and only a small number of strategies that may lead to materials with continuously adjustable characteristics have been reported1-3. Here we introduce adaptive surfaces made of a liquid film supported by a nanoporous elastic substrate. As the substrate deforms, the liquid flows within the pores causing the smooth and defect-free surface to roughen through a continuous range of topographies. We show that a graded mechanical stimulus can be directly translated into finely tuned, dynamic adjustments of optical transparency and wettability. In particular, we demonstrate simultaneous control of the film{\textquoteright}s transparency and its ability to continuously manipulate various low-surface-tension droplets from free-sliding to pinned. This strategy should make possible the rational design of tunable, multifunctional adaptive materials for a broad range of applications.}, doi = {doi:10.1038/nmat3598}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:27417438}, author = {X. Yao and Hu, Y. and Grinthal, A. and T.-S. Wong and L. Mahadevan and Aizenberg, J.} } @article {837446, title = {An artificial vasculature for adaptive thermal control of windows}, journal = {Solar Energy Materials and Solar Cells}, volume = {117}, year = {2013}, note = {BDH, IW,andDEIplannedtheresearch.BDHandIWfabricated devices andperformedtheexperiments.MKaidedinoptical transparencymeasurements.MJHdevelopedthetheoretical model. BDH,DEI,IW,JA,andMJHwrotethepaper.Allauthors revised thedocumentandagreedonits final contents.Wealso thank ShuyunWuforhisworkintheearlyphaseofthisproject.}, pages = {429-436}, abstract = {Windows are a major source of energy inefficiency in buildings. In addition, heating by thermal radiation reduces the efficiency of photovoltaic panels. To help reduce heating by solar absorption in both of these cases, we developed a thin, transparent, bio-inspired, convective cooling layer for building windows and solar panels that contains microvasculature with millimeter-scale, fluid-filled channels. The thin cooling layer is composed of optically clear silicone rubber with microchannels fabricated using microfluidic engineering principles. Infrared imaging was used to measure cooling rates as a function of flow rate and water temperature. In these experiments, flowing room temperature water at 2\ mL/min reduced the average temperature of a model 10{\texttimes}10\ cm2\ window by approximately 7{\textendash}9\ {\textdegree}C. An analytic steady-state heat transfer model was developed to augment the experiments and make more general estimates as functions of window size, channel geometry, flow rate, and water temperature. Thin cooling layers may be added to one or more panes in multi-pane windows or as thin film non-structural central layers. Lastly, the color, optical transparency and aesthetics of the windows could be modulated by flowing different fluids that differ in their scattering or absorption properties.}, doi = {10.1016/j.solmat.2013.06.027}, url = {https://doi.org/10.1016/j.solmat.2013.06.027}, author = {B.D. Hatton and I. Wheeldon and M.J. Hancock and Kolle, M. and Aizenberg, J. and D.E. Ingber} } @article {837396, title = {Bacterial flagella explore microscale hummocks and hollows to increase adhesion}, journal = {Proc. Nat. Acad. Sci.}, volume = {110}, year = {2013}, note = {We thank Karen Fahrner for helpful discussions about flagella and bacterial swimming behavior, and Michael Bucaro and Wendong Wang for helpful experimental discussions. This work was par- tially funded by the Office of Naval Research under the award N00014-11-1- 0641 and by the BASF Advanced Research Initiative at Harvard University. R.S.F. is supported by the National Science Foundation (NSF) Graduate Research Fellowship Program. Part of this work was carried out through the use of the Massachusetts Institute of Technology{\textquoteright}s Microsystems Technology Laboratories and the Center for Nanoscale Systems at Harvard University, a member of the National Nanotechnology Infrastructure Network, sup- ported by the NSF under Award ECS-0335765.}, pages = {5624-5629}, abstract = {Biofilms, surface-bound communities of microbes, are economically and medically important due to their pathogenic and obstructive properties. Among the numerous strategies to prevent bacterial adhesion and subsequent biofilm formation, surface topography was recently proposed as a highly nonspecific method that does not rely on small-molecule antibacterial compounds, which promote resistance. Here, we provide a detailed investigation of how the introduction of submicrometer crevices to a surface affects attachment of\ Escherichia coli. These crevices reduce substrate surface area available to the cell body but increase overall surface area. We have found that, during the first 2 h, adhesion to topographic surfaces is significantly reduced compared with flat controls, but this behavior abruptly reverses to significantly increased adhesion at longer exposures. We show that this reversal coincides with bacterially induced wetting transitions and that flagellar filaments aid in adhesion to these wetted topographic surfaces. We demonstrate that flagella are able to reach into crevices, access additional surface area, and produce a dense, fibrous network. Mutants lacking flagella show comparatively reduced adhesion. By varying substrate crevice sizes, we determine the conditions under which having flagella is most advantageous for adhesion. These findings strongly indicate that, in addition to their role in swimming motility, flagella are involved in attachment and can furthermore act as structural elements, enabling bacteria to overcome unfavorable surface topographies. This work contributes insights for the future design of antifouling surfaces and for improved understanding of bacterial behavior in native, structured environments.}, doi = {10.1073/pnas.1219662110}, url = {https://doi.org/10.1073/pnas.1219662110}, author = {R.S. Friedlander and H. Vlamakis and Kim, P. and Khan, M. and Kolter, R. and Aizenberg, J.} } @article {837461, title = {Biofilm attachment reduction on bioinspired, dynamic, microwrinkling surfaces}, journal = {New J. Phys}, volume = {15}, year = {2013}, note = {We thank Tom Blough for valuable assistance with tensile system upgrade work and integration, Jack Alvarenga for assistance with substrate fabrication development, Ilana Kolodkin for advice and culturing medium and the Professor Losick Lab (Harvard Department of Molecular and Cellular Biology) for use of autoclave facilities. DH was funded by the NSF Research Experience for Undergraduates (REU) program under award no. DMR-0820484. This work was funded in part by the Office of Naval Research under award no. N00014-11-1-0641 and BASF Advanced Research Initiative at Harvard University.}, pages = {095018}, abstract = {Most bacteria live in multicellular communities known as biofilms that are adherent to surfaces in our environment, from sea beds to plumbing systems. Biofilms are often associated with clinical infections, nosocomial deaths and industrial damage such as bio-corrosion and clogging of pipes. As mature biofilms are extremely challenging to eradicate once formed, prevention is advantageous over treatment. However, conventional surface chemistry strategies are either generally transient, due to chemical masking, or toxic, as in the case of leaching marine antifouling paints. Inspired by the nonfouling skins of echinoderms and other marine organisms, which possess highly dynamic surface structures that mechanically frustrate bio-attachment, we have developed and tested a synthetic platform based on both uniaxial mechanical strain and buckling-induced elastomer microtopography. Bacterial biofilm attachment to the dynamic substrates was studied under an array of parameters, including strain amplitude and timescale (1{\textendash}100\ mm\ s-1), surface wrinkle length scale, bacterial species and cell geometry, and growth time. The optimal conditions for achieving up to \ ~\ 80\%\ Pseudomonas aeruginosa\ biofilm reduction after 24\ h growth and \ ~\ 60\% reduction after 48\ h were combinatorially elucidated to occur at 20\% strain amplitude, a timescale of less than \ ~\ 5\ min between strain cycles and a topography length scale corresponding to the cell dimension of \ ~\ 1\ μm. Divergent effects on the attachment of\ P. aeruginosa,\ Staphylococcus aureus\ and\ Escherichia coli\ biofilms showed that the dynamic substrate also provides a new means of species-specific biofilm inhibition, or inversely, selection for a desired type of bacteria, without reliance on any toxic or transient surface chemical treatments.}, doi = {10.1088/1367-2630/15/9/095018}, url = {http://iopscience.iop.org/article/10.1088/1367-2630/15/9/095018/meta}, author = {A.K Epstein and D. Hong and Kim, P. and Aizenberg, J.} } @article {837381, title = {Bio-Inspired Band-Gap Tunable Elastic Optical Multilayer Fibers}, journal = {Adv. Mater.}, volume = {25}, year = {2013}, note = {The authors thank Dr. Silvia Vignolini and Dr. Beverly J. Glover for their helpful comments on the manuscript, Tom Blough for building a custom-made, remote-controlled micro-stretcher for fiber band-gap tuning and Dr. Paula Rudall and Dr. Stuart Blackman for kindly providing some M. nobilis fruit samples to start the investigation. Financial support from the US Air Force Office of Scientific Research Multidisciplinary University Research Initiative under award numbers FA9550-09-1-0669-DOD35CAP, FA9550-10-1-0020 and the UK Engineering and Physical Sciences Research Council EP/G060649/1 is gratefully acknowledged. M.Ko. acknowledges the financial support from the Alexander von Humboldt Foundation in form of a Feodor Lynen postdoctoral research fellowship. This work was performed in part at the Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Infrastructure Network (NNIN), which is supported by the National Science Foundation under NSF award no. ECS-0335765. CNS is part of Harvard University.}, pages = {2239-2245}, doi = {10.1002/adma.201203529}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:10235986}, author = {Kolle, M. and A. Lethbridge and M. Kreysing and J.J. Baumberg and Aizenberg, J. and P. Vukusic} } @article {837416, title = {Buckling-Induced Reversible Symmetry Breaking and Amplification of Chirality Using Supported Cellular Structures}, journal = {Adv. Mater.}, volume = {25}, year = {2013}, note = {This work was supported by Army Research Office MURI award W911NF-09-1-0476 and the Materials Research Science and Engineering Center under NSF Award No. DMR-0820484. K.B. acknowledges support Supporting Information is available from the Wiley Online Library or from the author. Acknowledgements This work was supported by Army Research Office MURI award W911NF-09-1-0476 and the Materials Research Science and Engineering Center under NSF Award No. DMR-0820484. K.B. acknowledges support Adv. Mater. 2013, {\textcopyright} 2013 WILEY-VCH Verlag GmbH \& Co. KGaA, Weinheim DOI: 10.1002/adma.201300617 of the Wyss institute through the Seed Grant Program and NSF-CMMI- 1149456-CAREER. We acknowledge the use of the facilities at the Harvard Center for Nanoscale Systems supported by NSF Award No. ECS-0335765 and MIT Microsystems Technology Laboratories. W.L.N. acknowledges the Netherlands Organization for Scientific Research for financial support. We thank Dr. James Weaver for help with macroscale structure preparation, Tom de Geus and Bas Overvelde for discussions, and Dr. Jayson Paulose and Dr. Andrej Kosmrlj for helpful comments.}, pages = {3380-3385}, doi = {10.1002/adma.201300617}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201300617}, author = {S. H. Kang and S. Shan and W.L. Noorduin and Khan, M. and Aizenberg, J. and Bertoldi, K.} } @article {837386, title = {Chemo-Mechanically Regulated Oscillation of an Enzymatic Reaction}, journal = {Chem. Mater.}, volume = {25}, year = {2013}, note = {The authors thank M. Aizenberg for valuable advice on this work and help with manuscript preparation and A. Ehrlicher and T. Kodger for technical assistance with luminescence imaging using a confocal microscope. This work was supported bytheUSDOEunderAwardNo.DE-SC0005247.}, pages = {521-523}, doi = {10.1021/cm303313a}, url = {https://pubs.acs.org/doi/abs/10.1021/cm303313a}, author = {He, X. and R.S. Friedlander and L. D. Zarzar and Aizenberg, J.} } @article {837476, title = {Creating bio-inspired hierarchical 3D{\textendash}2D photonic stacks via planar lithography on self-assembled inverse opals}, journal = {Bioinspiration \& Biomimetics}, volume = {8}, year = {2013}, note = {We thank L Mishchenko, B D Hatton, N Koay, and B A Nerger for helpful discussions. This work was supported by the AFOSR Award FA9550-09-1-0669-DOD35CAP. IBB acknowledges support from the Natural Sciences and Engineering Research Council of Canada through the PGS-D program.}, pages = {045004}, abstract = {Structural hierarchy and complex 3D architecture are characteristics of biological photonic designs that are challenging to reproduce in synthetic materials. Top{\textendash}down lithography allows for designer patterning of arbitrary shapes, but is largely restricted to planar 2D structures. Self-assembly techniques facilitate easy fabrication of 3D photonic crystals, but controllable defect-integration is difficult. In this paper we combine the advantages of top{\textendash}down and bottom{\textendash}up fabrication, developing two techniques to deposit 2D-lithographically-patterned planar layers on top of or in between inverse-opal 3D photonic crystals and creating hierarchical structures that resemble the architecture of the bright green wing scales of the butterfly,\ Parides sesostris. These fabrication procedures, combining advantages of both top{\textendash}down and bottom{\textendash}up fabrication, may prove useful in the development of omnidirectional coloration elements and 3D{\textendash}2D photonic crystal devices.}, doi = {10.1088/1748-3182/8/4/045004}, url = {http://iopscience.iop.org/article/10.1088/1748-3182/8/4/045004/meta}, author = {Burgess, I.B. and Aizenberg, J. and Loncar, M.} } @article {837456, title = {Enhancement of absorption and color contrast in ultra-thin highly absorbing optical coatings}, journal = {Appl. Phys. Lett.}, volume = {103}, year = {2013}, note = {We acknowledge the financial support from the Air Force Office of Scientific Research under grant numbers FA9550-12-1-0289 and FA9550-09-1-0669-DOD35CAP. M. Kats was supported by the National Science Foundation through a Graduate Research Fellowship. M. Kolle was sup- ported by the Alexander-von-Humboldt Foundation. The thin film depositions were performed at the Harvard Center for Nanoscale Systems, which is a member of the National Nanotechnology Infrastructure Network.}, pages = {101104}, abstract = {Recently a new class of optical interference\ coatings\ was introduced which comprises ultra-thin, highly absorbing\ dielectric\ layers on metal substrates. We show that these lossy\ coatings\ can be augmented by an additional transparent subwavelength layer. We fabricated a sample comprising a\ gold\ substrate, an ultra-thin film of\ germanium\ with a thickness gradient, and several alumina\ films.\ The experimental\ reflectivity\ spectra\ showed that the additional alumina layer increases the color range that can be obtained, in agreement with calculations. More generally, this transparent layer can be used to enhance\ optical absorption,\ protect against erosion, or as a transparent electrode for optoelectronic devices.}, doi = {10.1063/1.4820147}, url = {https://doi.org/10.1063/1.4820147}, author = {M. A. Kats and S. J. Byrnes and R. Blanchard and Kolle, M. and P. Genevet and Aizenberg, J. and F. Capasso} } @article {837391, title = {Hierarchical or Not? Effect of the Length Scale and Hierarchy of the Surface Roughness on Omniphobicity of Lubricant-Infused Substrates}, journal = {Nano Lett.}, volume = {13}, year = {2013}, note = {This research was supported by the ONR under the awards $\#$N00014-12-1-0962 (fabrication of non- fouling surfaces on various materials), $\#$N00014-12-1-0875 (shear-dependent behavior) and AFOSR under the award $\#$FA9550-09-1-0669-DOD35CAP (optical properties). Part of this work was performed at the Centre for Nanoscale Systems (CNS) at Harvard University, supported under NSF award $\#$ECS- 0335765. We thank Honeywell-Sperian for providing polycarbonate lens samples, FLEXcon for providing aluminized PET sheet samples. We thank Mr Onye Ahanotu for SEM images of sandblasted aluminum and pictures of aluminized plastic films, and Dr Alison Grinthal and Mr Noah McCallum for providing comments on the manuscript.}, pages = {1793-1799}, abstract = {Lubricant-infused textured solid substrates are gaining remarkable interest as a new class of omni-repellent nonfouling materials and surface coatings. We investigated the effect of the length scale and hierarchy of the surface topography of the underlying substrates on their ability to retain the lubricant under high shear conditions, which is important for maintaining nonwetting properties under application-relevant conditions. By comparing the lubricant loss, contact angle hysteresis, and sliding angles for water and ethanol droplets on flat, microscale, nanoscale, and hierarchically textured surfaces subjected to various spinning rates (from 100 to 10 000 rpm), we show that lubricant-infused textured surfaces with uniform nanofeatures provide the most shear-tolerant liquid-repellent behavior, unlike lotus leaf-inspired superhydrophobic surfaces, which generally favor hierarchical structures for improved pressure stability and low contact angle hysteresis. On the basis of these findings, we present generalized, low-cost, and scalable methods to manufacture uniform or regionally patterned nanotextured coatings on arbitrary materials and complex shapes. After functionalization and lubrication, these coatings show robust, shear-tolerant omniphobic behavior, transparency, and nonfouling properties against highly contaminating media.}, doi = {10.1021/nl4003969}, url = {https://pubs.acs.org/doi/abs/10.1021/nl4003969}, author = {Kim, P. and M.J. Kreder and J. Alvarenga and Aizenberg, J.} } @inbook {837431, title = {Hydrogel-Actuated Integrated Responsive Systems (HAIRS): Creating Cilia-like "Hairy" Surfaces}, year = {2013}, note = {This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award $\#$DE-SC0005247. This work is based on the research of Dr. P. Kim, L. Zarzar, Dr. B. Pokroy, Dr. S.H. Kang, A. Epstein, Dr. X. He, Dr. M. Aizenberg, Dr. M. Matsunaga, and Dr. M. Khan.}, pages = {162-185}, publisher = {RSC}, organization = {RSC}, address = {Cambridge, U.K.}, author = {Grinthal, A. and Aizenberg, J.}, editor = {J. den Toonder and P. Onck} } @article {837361, title = {Hydroglyphics: Demonstration of Selective Wetting on Hydrophilic and Hydrophobic Surfaces}, journal = {J. Chem. Educ.}, year = {2013}, note = {

The development of this demonstration was supported by the Materials Research Science and Engineering Center at Harvard University through Research Experience for Teachers program funded by National Science Foundation (NSF-DMR-0820484) and by the U.S. Air Force Office of Scientific Research Multidisciplinary University Research Initiative under award number FA9550-09-1-0669-DOD35CAP (optical properties). We thank Merrimack High School students Austin James Knust, Sidney Herring, and Olivia Davis for the help in the modification of Tesla coils and testing different stickers. We thank Kathryn Hollar (Harvard University), Karine Thate (Museum of Science, Boston), and Michael J. Kreder (Wyss Institute) for discussions and support.

}, doi = {10.1021/ed3003308}, url = {https://pubs.acs.org/doi/abs/10.1021/ed3003308}, author = {Kim, P. and J. Alvarenga and Aizenberg, J. and R.S. Sleeper} } @article {837366, title = {Inhibition of Ice Nucleation by Slippery Liquid-Infused Porous Surfaces (SLIPS)}, journal = {Physical Chemistry Chemical Physics}, volume = {15}, year = {2013}, note = {

We thank Dr Tony Haymet for many helpful discussions and suggestions.

}, pages = {581-585}, abstract = {Ice repellent coatings have been studied and keenly sought after for many years, where any advances in the durability of such coatings will result in huge energy savings across many fields. Progress in creating anti-ice and anti-frost surfaces has been particularly rapid since the discovery and development of slippery, liquid infused porous surfaces (SLIPS). Here we use SLIPS-coated differential scanning calorimeter (DSC) pans to investigate the effects of the surface modification on the nucleation of supercooled\ water. This investigation is inherently different from previous studies which looked at the adhesion of ice to SLIPS surfaces, or the formation of ice under high humidity conditions. Given the stochastic nature of nucleation of ice from supercooled\ water, multiple runs on the same sample are needed to determine if a given surface coating has a real and statistically significant effect on the nucleation temperature. We have cycled supercooling to freezing and then thawing of deionized\ water\ in hydrophilic (untreated aluminum), hydrophobic, superhydrophobic, and SLIPS-treated DSC pans multiple times to determine the effects of surface treatment on the nucleation and subsequent growth of ice. We find that SLIPS coatings lower the nucleation temperature of supercooled\ water\ in contact with statistical significance and show no deterioration or change in the coating performance even after 150 freeze{\textendash}thaw cycles.}, doi = {10.1039/C2CP43586A}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:27663226}, author = {P.W. Wilson and W. Lu and H. Xu and Kim, P. and M.J. Kreder and J. Alvarenga and Aizenberg, J.} } @article {837426, title = {Lubricant-infused micro/nano-structured surfaces with tunable dynamic omniphobicity at high temperatures}, journal = {Appl. Phys. Lett.}, volume = {102}, year = {2013}, note = {We thank P. Kim for helpful discussions regarding TGA. M.N.M. gratefully acknowledges a Fannie and John Hertz Foundation Graduate Fellowship and a NSF Graduate Research Fellowship. The work was supported partially by the ONR MURI Award No. N00014-12-1-0875 and by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DEAR0000326. We acknowledge the use of the facilities at the Harvard Center for Nanoscale Systems supported by the NSF under Award No. ECS-0335765.}, pages = {231603}, abstract = {Omniphobic\ surfaces\ that can repel fluids at temperatures higher than 100 {\textdegree}C are rare. Most state-of-the-art\ liquid-repellent\ materials are based on the lotus effect, where a thin air layer is maintained throughout micro/nanotextures leading to high mobility of\ liquids.\ However, such behavior eventually fails at elevated temperatures when the\ surface tension\ of test\ liquids\ decreases significantly. Here, we demonstrate a class of lubricant-infused\ structuredsurfaces\ that can maintain a robust omniphobic state even for low-surface-tension\ liquids\ at temperatures up to at least 200 {\textdegree}C. We also demonstrate how\ liquid\ mobility on such\ surfaces\ can be tuned by a factor of 1000.}, doi = {10.1063/1.4810907}, url = {http://nrs.harvard.edu/urn-3:HUL.InstRepos:27738667}, author = {D. Daniel and M.N. Mankin and R.A. Belisle and T.-S. Wong and Aizenberg, J.} } @article {837406, title = {Rational Design of Mechano-Responsive Optical Materials by Fine Tuning the Evolution of Strain-Dependent Wrinkling Patterns}, journal = {Adv. Optical Mater.}, volume = {1}, year = {2013}, note = {This work was supported by U.S. AFOSR Multidisciplinary University Research Initiative under award number FA9550{\textendash}09{\textendash}1{\textendash}0669- DOD35CAP. Part of this work was performed at the Center for Nanoscale Systems (CNS) at Harvard University supported by the NSF under award no. ECS-0335765. We thank Prof. John Hutchinson for discussions of the theoretical explanations, Chuck Hoberman for discussions of the applications of wrinkled PDMS, and Dr. Alison Grinthal for the critical comments on the manuscript. We thank Tom Blough for the design and fabrication of customized stretching devices and frames and Dr. James C. Weaver for the graphical illustrations of wrinkled PDMS sheets.}, pages = {381-388}, abstract = {Rational design strategies for mechano-responsive optical material systems are created by introducing a simple experimental system that can continuously vary the state of bi-axial stress to induce various wrinkling patterns, including stripes, labyrinths, herringbones, and rarely observed checkerboards, that can dynamically tune the optical properties. In particular, a switching of two orthogonally oriented stripe wrinkle patterns from oxidized polydimethylsiloxane around the critical strain value is reported, as well as the coexistence of these wrinkles forming elusive checkerboard patterns, which are predicted only in previous simulations. These strain-induced wrinkle patterns give rise to dynamic changes in optical transmittance and diffraction patterns. A theoretical description of the observed pattern formation is presented which accounts for the residual stress in the membrane and allows for the fine-tuning of the window of switching of the orthogonal wrinkles. Applications of wrinkle-induced changes in optical properties are demonstrated, including a mechanically responsive instantaneous privacy screen and a transparent sheet that reversibly reveals a message or graphic and dynamically switches the transmittance when stretched and released.}, doi = {10.1002/adom.201300034}, url = {https://doi.org/10.1002/adom.201300034}, author = {Kim, P. and Hu, Y. and J. Alvarenga and Kolle, M. and Suo, Z. and Aizenberg, J.} } @article {837421, title = {Rationally Designed Complex Hierarchical Microarchitectures}, journal = {Science}, volume = {340}, year = {2013}, note = {We thank J. C. Weaver for advice with the SEM imaging, S. K. Y. Tang and R. Sadza for the microfluidic experiments, L. Hendriks for growing the structures in Fig. 5F, and A. J. Aizenberg for help with the manuscript. This work was supported by the NSF Materials Research Science and Engineering Centers under award no. DMR-0820484. W.L.N. thanks the Netherlands Organization for Scientific Research for financial support. EM was performed at Harvard{\textquoteright}s Center for Nanoscale Systems, supported by the NSF under award no. ECS-0335765.}, pages = {832-837}, abstract = {The emergence of complex nano- and microstructures is of fundamental interest, and the ability to program their form has practical ramifications in fields such as optics, catalysis, and electronics. We developed carbonate-silica microstructures in a dynamic reaction-diffusion system that allow us to rationally devise schemes for precisely sculpting a great variety of elementary shapes by diffusion of carbon dioxide (CO2) in a solution of barium chloride and sodium metasilicate. We identify two distinct growth modes and show how continuous and discrete modulations in CO2\ concentration, pH, and temperature can be used to deterministically switch between different regimes and create a bouquet of hierarchically assembled multiscale microstructures with unprecedented levels of complexity and precision. These results outline a nanotechnology strategy for "collaborating" with self-assembly processes in real time to build arbitrary tectonic architectures.}, doi = {10.1126/science.1234621}, url = {http://science.sciencemag.org/content/340/6134/832}, author = {Noorduin, W. and Grinthal, A. and L. Mahadevan and Aizenberg, J.} } @article {837436, title = {Spatial Control of Condensation and Freezing on Superhydrophobic Surfaces with Hydrophilic Patches}, journal = {Adv. Funct. Mater.}, volume = {23}, year = {2013}, note = {The authors would like to acknowledge the assistance of Dr. Mughees Khan (Wyss Institute for Bio-inspired Engineering) in the fabrication of the arrays structures. The work was partially supported by the ARPA-E under award $\#$: DE-AR0000326. The work was performed in part at the Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Infrastructure Network (NNIN), which is supported by the National Science Foundation under Award ECS-0335765. L.M. thanks the US Department of Homeland Security (DHS) for the fellowship. The DHS Scholarship and Fellowship Program is administered by the Oak Ridge Institute for Science and Education (ORISE) through an interagency agreement between the US Department of Energy (DOE) and DHS. ORISE is managed by Oak Ridge Associated Universities (ORAU) under DOE Contract DE-AC05-06OR23100.}, pages = {4577-4584}, abstract = {Certain natural organisms use micro-patterned surface chemistry, or ice-nucleating species, to control water condensation and ice nucleation for survival under extreme conditions. As an analogy to these biological approaches, it is shown that functionalized, hydrophilic polymers and particles deposited on the tips of superhydrophobic posts induce precise topographical control over water condensation and freezing at the micrometer scale. A bottom-up deposition process is used to take advantage of the limited contact area of a non-wetting aqueous solution on a superhydrophobic surface. Hydrophilic polymer deposition on the tips of these geometrical structures allows spatial control over the nucleation, growth, and coalescence of micrometer-scale water droplets. The hydrophilic tips nucleate water droplets with extremely uniform nucleation and growth rates, uniform sizes, an increased stability against coalescence, and asymmetric droplet morphologies. Control of freezing behavior is also demonstrated via deposition of ice-nucleating AgI nanoparticles on the tips of these structures. This combination of the hydrophilic polymer and AgI particles on the tips was used to achieve templating of ice nucleation at the micrometer scale. Preliminary results indicate that control over ice crystal size, spatial symmetry, and position might be possible with this method. This type of approach can serve as a platform for systematically analyzing micrometer-scale condensation and freezing phenomena, and as a model for natural systems.}, doi = {10.1002/adfm.201300418}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.201300418}, author = {L. Mishchenko and Aizenberg, J. and B.D. Hatton} } @article {837441, title = {Structural Colour in Colourimetric Sensors and Indicators}, journal = {J. Mater. Chem. C}, volume = {1}, year = {2013}, note = {This work was supported by the AFOSR Award $\#$ FA9550-09-1- 0669-DOD35CAP.}, pages = {6075-6086}, abstract = {Colourimetric sensors and\ indicators\ are widely used because of their low cost and simplicity. A significant challenge associated with the design of this type of device is that the sensing mechanism must be simultaneously optimised for the sensitivity of the response and a visually perceptible colour change. Structural colour, derived from coherent scattering rather than molecular absorption, is a promising route to colourimetric sensor design because colour shifts are tied to changes in one of many physical properties of a material, rather than a specific chemical process. This Feature Article presents an overview of the development of low-cost sensors and\ indicators\ that exploit structural colour. Building upon recent advances in structurally adaptive materials design, structural colour sensors have been developed for a wide variety of previously inaccessible physical (e.g.\ temperature, strain, electric fields) and chemical stimuli (e.g.\ small\ organic molecules, charged species,\ biomacromolecules\ and\ metabolites). These devices, often exceeding the state of the art in performance, simplicity or both, have bright prospects for market impact in areas such as environmental monitoring, workplace hazard identification, threat detection, and point-of-care diagnostics. Finding the ideal balance between performance (e.g.\ sensitivity, specificity, reproducibility,\ etc.) and simplicity (e.g.\ colourimetric\ vs.\ spectroscopic readout) will be one of the most critical elements in the further development of structural colour sensors. This balance should be driven largely by the market demands and competing technologies.}, doi = {10.1039/C3TC30919C}, url = {http://pubs.rsc.org/en/content/articlelanding/2013/tc/c3tc30919c$\#$!divAbstract}, author = {Burgess, I.B. and Loncar, M. and and J. Aizenberg} } @article {837451, title = {Transparency and damage tolerance of patternable omniphobic lubricated surfaces based on inverse colloidal monolayers}, journal = {Nature Communications}, volume = {4}, year = {2013}, note = {N.V. acknowledges funding from the Leopoldina Fellowship Programme. Wendong Wang and Stefanie Utech are acknowledged for discussions on the modelling of lubricant de-wetting. Jack Alvarenga is acknowledged for help with the ice adhesion setup. The work was supported by the Advanced Research Projects Agency-Energy (ARPA-E) under award number DE-AR0000326 (fabrication and surface properties) and by the Air Force Office of Scientific Research (AFOSR) under award number FA9550-09-0669-DOD35CAP (optical properties). This work was performed in part at the Harvard Center for Nanoscale Systems (CNS) supported by the National Science Foundation (NSF) under award number ECS-0335765.}, abstract = {A transparent coating that repels a wide variety of liquids, prevents staining, is capable of self-repair and is robust towards mechanical damage can have a broad technological impact, from solar cell coatings to self-cleaning optical devices. Here we employ colloidal templating to design transparent, nanoporous surface structures. A lubricant can be firmly locked into the structures and, owing to its fluidic nature, forms a defect-free, self-healing interface that eliminates the pinning of a second liquid applied to its surface, leading to efficient liquid repellency, prevention of adsorption of liquid-borne contaminants, and reduction of ice adhesion strength. We further show how this method can be applied to locally pattern the repellent character of the substrate, thus opening opportunities to spatially confine any simple or complex fluids. The coating is highly defect-tolerant due to its interconnected, honeycomb wall structure, and repellency prevails after the application of strong shear forces and mechanical damage. The regularity of the coating allows us to understand and predict the stability or failure of repellency as a function of lubricant layer thickness and defect distribution based on a simple geometric model.}, doi = {10.1038/ncomms3176}, url = {https://www.nature.com/articles/ncomms3176}, author = {Vogel, N. and R.A. Belisle and Hatton, B. and Wong, T.S. and Aizenberg, J.} } @article {837316, title = {Combinatorial Wetting in Colour: An Optofluidic Nose}, journal = {Lab on a Chip}, volume = {12}, year = {2012}, note = {We thank A. Shneidman, K.R. Phillips, N. Vogel, N. Clarke and N. Koay for helpful discussions. This work was supported by the AFOSR Award $\#$ FA9550-09-1-0669-DOD35CAP. IBB acknowl- edges support from the Natural Sciences and Engineering Research Council of Canada through the PGS-D program.}, pages = {3666-3669}, doi = {10.1039/C2LC40489C}, author = {K.P. Raymond and Burgess, I.B. and M.H. Kinney and Loncar, M. and Aizenberg, J.} } @article {837281, title = {Enriching libraries of high-aspect-ratio micro- or nanostructures by rapid, low-cost, benchtop nanofabrication}, journal = {Nature Protocols}, volume = {7}, year = {2012}, note = {This work was partially supported by the US Department of Energy, Office of Basic Energy Sciences and the Division of Materials Science and Engineering, under award no. DE-SC0005247 (design of HAR structures); the US Army Research Office Multidisciplinary University Research Initiative under award no. W911NF-09-1-0476 (electrodeposition and mechanical properties); and the US Air Force Office of Scientific Research Multidisciplinary University Research Initiative under award no. FA9550-09-1-0669-DOD35CAP (optical properties). This work was carried out in part through the use of the Massachusetts Institute of Technology{\textquoteright}s Microsystems Technology Laboratories. Part of this work was also performed at the Center for Nanoscale Systems at Harvard University, a member of the National Nanotechnology Infrastructure Network, which is supported by the National Science Foundation (NSF) under NSF award no. ECS-0335765. W.E.A.-M. thanks REU BRIDGE, co-funded by the ASSURE program of the Department of Defense in partnership with the National Science Foundation REU Site program under NSF grant no. DMR-1005022. We thank J.C. Weaver for help in manuscript preparation and E. Macomber for technical assistance with metal deposition equipment.}, pages = {311{\textendash}327}, doi = {10.1038/nprot.2012.003}, author = {Kim, P. and W.E. Adorno-Martinez and Khan, M. and and J. Aizenberg} } @article {837331, title = {Fine-Tuning the Degree of Stem Cell Polarization and Alignment on Ordered Arrays of High-Aspect-Ratio Nanopillars}, journal = {ACS Nano}, volume = {6}, year = {2012}, note = {This work was supported by the DOE under Award No. DE-SC0005247. We acknowledge the use of the facilities at the Harvard Center for Nanoscale Systems supported by NSF Award No. ECS-0335765. We would like to thank D. Ingber for fruitful discussions and A. Epstein for AFM work.}, pages = {6222-6230}, doi = {10.1021/nn301654e}, author = {M. A. Bucaro and Vasquez, Y. and B.D. Hatton and and J. Aizenberg} } @article {837321, title = {Liquid-Infused Nanostructured Surfaces with Extreme Anti-Ice and Anti-Frost Performance}, journal = {ACS Nano}, volume = {6}, year = {2012}, note = {This research was supported by the MRSEC under NSF award $\#$DMR-1005022. Part of this work was performed at the Center for Nanoscale Systems (CNS) at Harvard University, supported under NSF award $\#$ECS-0335765. TSW would like to thank the Croucher Foundation Postdoctoral Fellowship. WAM would like to thank REU BRIDGE, co-funded by the ASSURE program of the DoD in partnership with the NSF REU Site program under NSF Grant $\#$DMR- 1005022. We thank Dr. Mike Heidenreich (Luvata, LLC) for kindly providing aluminum samples. We thank Tom Blough for technical assistance in building ice adhesion test setup, Drs. Michael Aizenberg, Alison Grinthal, and Mughees Khan for their comments in manuscript preparation.}, pages = {6569-6577}, doi = {10.1021/nn302310q}, author = {Kim, P. and Wong, T.S. and J. Alvarenga and M.J. Kreder and W.E. Adorno-Martinez and Aizenberg, J.} } @article {837346, title = {Liquid-infused structured surfaces with exceptional anti-biofouling performance}, journal = {Proc. Nat. Acad. Sci. USA}, volume = {109}, year = {2012}, note = {We thank Allon Hochbaum for helpful discussion on toxicity and manuscript advice, Ben Hatton and James Weaver for supplying the peristaltic pump and the flow cell, Ilana Kolodkin-Gal for microbiological advice and materials, and Meredith Duffy for additional assistance. TSW thanks Croucher Foundation Postdoctoral Fellowship for financial support. The work was partially supported by the Wyss Institute for Biologically In- spired Engineering at Harvard University and ONR under the award N00014-11-1-0641.}, pages = {13182-13187}, doi = {10.1073/pnas.1201973109}, author = {A.K Epstein and Wong, T.S. and R.A. Belisle and E.M. Boggs and Aizenberg, J.} } @article {837376, title = {Mucin Biopolymers Prevent Bacterial Aggregation by Retaining Cells in the Free-Swimming State}, journal = {Current Biology}, volume = {22}, year = {2012}, note = {This work was supported by the Cystic Fibrosis Foundation CFF grant number RIBBEC08I0 and MIT startup funds to K.R. K.R.F. is supported by European Research Council grant 242670. R.S.F. is supported through the National Science Foundation Graduate Research Fellowship Program. We thank D.J. Wozniak for the EPS deletion strains, B. Berwin for providing the P. aeruginosa PA14 strains, W. Kim for the labeled conjugating strain, G.A. O{\textquoteright}Toole for the complementation vector, and the lab of R. Kolter for the E. coli strain ZK2686.}, pages = {2325-2330}, doi = {10.1016/j.cub.2012.10.028}, author = {M. Caldara and R.S. Friedlander and N.L. Kavanaugh and Aizenberg, J. and K.R. Foster and K. Ribbeck} } @article {837336, title = {Multifunctional Actuation Systems Responding to Chemical Gradients}, journal = {Soft Matter}, volume = {8}, year = {2012}, note = {We thank Dr P. Kim, Dr U. Salman, and Dr A. Grinthal for discussions and Dr A. Taylor and Dr M. Khan for substrate fabri- cation. This work was supported by the DOE under award DE- SC0005247. L. D. Z. thanks the DoD for support through the NDSEG Fellowship Program as well as the NSF for support through the Graduate Research Fellowship Program}, pages = {8289-8293}, doi = {10.1039/C2SM26064F}, author = {L. D. Zarzar and Liu, Q. and He, X. and Hu, Y. and Suo, Z. and Aizenberg, J.} } @article {837296, title = {Multiphoton Lithography of Nanocrystalline Platinum and Palladium for Site-Specific Catalysis in 3D Microenvironments}, journal = {J. Am. Chem. Soc.}, volume = {134}, year = {2012}, note = {We acknowledge support from U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences (BES), Division of Materials Sciences and Engineering under Award DE-SC0005247 and Catalysis Science Program (DE- FG02-02-ER15368). Work was performed, in part, at CINT, a U.S. DOE, BES user facility. L.D.Z. thanks the DOD-NDSEG, the NSF-GRF, and the NINE program at Sandia for support. Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. DOE National Nuclear Security Administration under contract DE- AC04-94AL85000.}, pages = {4007-4010}, doi = {10.1021/ja211602t}, author = {L. D. Zarzar and B.S. Swartzentruber and J.C. Harper and D.R. Dunphy and C. J. Brinker and Aizenberg, J. and and B. Kaehr} } @article {836866, title = {Patterning Hierarchy in Direct and Inverse Opal Crystals}, journal = {Small}, volume = {8}, year = {2012}, note = {This work was supported by the Air Force Office of Scientific Research Award $\#$ FA9550-09-1-0669- DOD35CAP. L.M. acknowl- edges fellowship support from the Department of Homeland Security (DHS). M.K. acknowledges funding from the Alexander von Humboldt Foundation. Electron microscopy and photolitho- graphy were performed at Harvard{\textquoteright}s Center for Nanoscale Systems. Fabrication was partially supported by the National Science Foun- dation{\textquoteright}s MRSEC Award $\#$DMR-0820484. We thank Dr. Mughees Khan for nanofabrication of the blade surface used in this work.}, pages = {1904-1911}, doi = {10.1002/smll.201102691}, author = {L. Mishchenko and Hatton, B. and Kolle, M. and Aizenberg, J.} } @article {837351, title = {Screening Conditions for Rationally Engineered Electrodeposition of Nanostructures (SCREEN): Electrodeposition and Applications of Polypyrrole Nanofibers using MIcrofluidic Gradients}, journal = {Small}, volume = {8}, year = {2012}, note = {This work was partially supported by the U.S. Department of Energy, Office of Basic Energy Sciences, and the Division of Materials Science and Engineering, under award number DE-SC0005247 (hierarchical nanostructure fabrication on high-aspect-ratio structures and 3D electrodes for hydrogel deposition), and the U.S. Air Force Office of Scientific Research Multidisciplinary University Research Initiative under award number FA9550-09-1-0669-DOD35CAP (optical properties). Part of this work was also performed at the Center for Nanoscale Systems (CNS) at Harvard University, a member of the National Nanotechnology Infrastructure Network (NNIN), which is supported by the National Science Foundation under NSF award no. ECS-0335765. We thank Prof. Robert Wood and Prof. George Whitesides for the use of equipment and Mr. Wilmer Adorno for technical assistance, and Dr. Michael Aizenberg for comments on the manuscript.}, pages = {3502-3509}, doi = {10.1002/smll.201200888}, author = {H. Burgoyne and Kim, P. and Kolle, M. and A.K Epstein and Aizenberg, J.} } @article {837371, title = {Secrets revealed - Spatially selective wetting of plasma-patterned periodic mesoporous organosilica}, journal = {Can. J. Chem.}, volume = {90}, year = {2012}, note = {Ellipsometry measurements and TEM imaging were performed at the Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Infrastructure Network (NNIN), which is supported by the National Science Foundation (NSF) under award No. ECS-0335765. CNS is part of Harvard University. This work was supported by the Air Force Office of Scientific Research (AFOSR), award No. FA9550- 09-1-0669-DOD35CAP. IBB acknowledges support from the Natural Sciences and Engineering Research Council of Canada (NSERC) through the Postgraduate Scholarship - Doctoral (PGS-D) program.}, pages = {1063-1068}, doi = {10.1139/v2012-092}, author = {W. Wang and Burgess, I.B. and B.D. Hatton and J. Alvarenga and Aizenberg, J.} } @article {837291, title = {Steering nanofibers: An integrative approach to bio-inspired fiber fabrication and assembly}, journal = {Nano Today}, volume = {7}, year = {2012}, note = {This work was partially supported by the Materials Research Science and Engineering Center under NSF Award no. DMR- 0820484 (fabrication) and by the DOE under Award no. DE-SC0005247. This work was performed in part at the Cen- ter for Nanoscale Systems (CNS) at Harvard University, a member of the National Nanotechnology Infrastructure Net- work (NNIN), which is supported by the National Science Foundation under NSF award no. ECS-0335765, and at the MIT{\textquoteright}s Microsystems Technology Laboratories.}, pages = {35-52}, doi = {10.1016/j.nantod.2011.12.005}, author = {Grinthal, A. and S. H. Kang and A. K. Epstein and Aizenberg, M. and Khan, M. and Aizenberg, J.} } @article {837136, title = {Structural Transformation by Electrodeposition on Patterned Substrates (STEPS) - A New Versatile Nanofabrication Method}, journal = {Nano Lett.}, volume = {12}, year = {2012}, note = {Research supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award $\#$DE-SC0005247 (fabrication of HAR structures) and by the U.S. Army Research Office Multi- disciplinary University Research Initiative under Award $\#$W911NF-04-1-0476 (reinforced structures). We thank Profes- sor Theodore Betley for the use of equipment, Dr. Alison Grinthal for helpful comments, and Dr. James C. Weaver for graphic artwork. This work was carried out in part through the use of MIT{\textquoteright}s Microsystems Technology Laboratories and Har- vard{\textquoteright}s Center for Nanoscale Systems (CNS).}, pages = {527-533}, doi = {10.1021/nl200426g}, author = {Kim, P. and A. K. Epstein and Khan, M. and L. D. Zarzar and D. J. Lipomi and G. M. Whitesides and and J. Aizenberg} } @article {837341, title = {Synthetic Homeostatic Materials with Chemo-Mechano-Chemical Self-Regulation}, journal = {Nature}, volume = {487}, year = {2012}, note = {We thank P. Kim for assistance with the gel formulation, M. Khan for microstructure fabrication, R. S. Friedlander for assistance with confocal imaging, M. Kolle and A. Ehrlicher for technical assistance, and A. Grinthal for help with manuscript preparation. The work was supported by the US DOE under award DE-SC0005247 (experiment) and by the US NSF under award CMMI-1124839 (computational modelling).}, pages = {214-218}, doi = {10.1038/nature11223}, author = {He, X. and Aizenberg, M. and Kuksenok, O. and L. D. Zarzar and Shastri, A. and Balazs, A.C. and Aizenberg, J.} } @article {837276, title = {Wetting in Color: Colorimetric Differentiation of Organic Liquids with High Selectivity}, journal = {ACS Nano}, volume = {6}, year = {2012}, note = {We thank T.L. Vu, A.V. Shneidman, L. Mishchenko, A.W. Rodriguez, B.D. Hatton, M. Aizenberg, and F. Spaepen for helpful discussions, and T.S. Wong for surface tension measurements. This work was supported by the AFOSR Award No. FA9550-09-1-0669-DOD35CAP. I.B.B. acknowledges support from the Natural Sciences and Engineering Research Council of Canada through the PGS-D program. M.K. acknowl- edges support from the Alexander von Humboldt Foundation. Electron microscopy was performed at Harvard{\textquoteright}s Center for Nanoscale Systems.}, pages = {1427-1437}, doi = {10.1021/nn204220c}, author = {Burgess, I.B. and N. Koay and K.P. Raymond and Kolle, M. and Loncar, M. and and J. Aizenberg} } @article {837356, title = {Writing on Superhydrophobic Nanopost Arrays: Topographic Design for Bottom-up Assembly}, journal = {Nano Letters}, volume = {12}, year = {2012}, note = {none}, pages = {4551-4557}, doi = {10.1021/nl301775x}, author = {B.D. Hatton and Aizenberg, J.} } @article {837106, title = {Bacterial biofilm shows persistent resistance to liquid wetting and gas penetration.}, journal = {Proc. Nat. Acad. Sci. USA}, volume = {108}, year = {2011}, note = {

We are grateful to Dr. Moshe Shemesh, Dr. Yunrong (Win) Chai, and Dr. Ilana Kolodkin-Gal (Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA) for providing plates and cul- tures as well as guidance in biological technique, to Dr. Hera Vlamakis and Dr. Allon Hochbaum for advice on biological protocols, and to Dr. Thomas Angelini for assistance with confocal microscopy. We thank Prof. Richard Losick for use of his laboratory facilities, Dr. Alison Grinthal for assistance with the manuscript, and Dr. Mark Rivers for training and help at Beamline 13-BMD at the Advanced Photon Source. This work was funded by the BASF Advanced Research Initiative at Harvard University. Use of the Advanced Photon Source was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract W-31-109-Eng-38.

}, pages = {995-1000}, doi = {10.1073/pnas.1011033108}, author = {A. K. Epstein and B. Pokroy and A. Seminara and Aizenberg, J.} } @article {837116, title = {Bio-inspired Design of Submerged Hydrogel-Actuated Polymer Microstructures Operating in Response to pH.}, journal = {Adv. Mater.}, volume = {23}, year = {2011}, note = {We thank Prof. A. Sidorenko and Dr. M. Aizenberg for discussions and Drs. Ashley Taylor and Mughees Kahn for substrate fabrication. This work was supported by the AFOSR under Award FA9550 {\textendash} 09-1 {\textendash} 0669-DOD35CAP and by the DOE under award DE-SC0005247. The work was performed in part at the Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Infrastructure Network (NNIN), which is supported by the NSF under award ECS-0335765. L. D. Z. thanks the Department of Defense (DoD) for support through the National Defense Science \& Engineering Graduate Fellowship (NDSEG) Program, as well as the National Science Foundation (NSF) for support through the Graduate Research Fellowship Program (GRFP).}, pages = {1442{\textendash}1446}, doi = {10.1002/adma.201004231}, author = {L. D. Zarzar and Kim, P. and Aizenberg, J.} } @article {837256, title = {Bioinspired self-repairing slippery surfaces with pressure-stable omniphobicity}, journal = {Nature}, volume = {477}, year = {2011}, note = {T.-S.W. acknowledges funding support from the Croucher Foundation Postdoctoral Fellowship. We thank K. E. Martin for help with the drop impact test. We also thank J. C. Weaver and P. Allen for help in manuscript preparation. The work was supported partially by the AFOSR MURI award FA9550-09-1-0669-DOD35CAP (optical properties), and ARO MURI award W911NF-09-1-0476 (robustness and self-repair). We acknowledge the use of the facilities at the Harvard Center for Nanoscale Systems supported by the NSF under award ECS-0335765.}, pages = {443-447}, doi = {10.1038/nature10447}, author = {T.-S. Wong and S. H. Kang and S.K.Y. Tang and E.J. Smythe and B.D. Hatton and Grinthal, A. and and J. Aizenberg} } @proceedings {837306, title = {Colloidal co-assembly route to large-area high-quality phototonic crystals}, volume = {7946}, year = {2011}, note = {This project was supported by the Office of Naval Research under Award N00014-07-1-0690-DOD35CAP and by the Air Force Office of Scientific Research under Award FA9550-09-1-0669-DOD35CAP. The work was performed in part at the Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Infrastructure Network (NNIN), which is supported by the National Science Foundation under Award ECS-0335765. L.M. thanks the US Department of Homeland Security (DHS) for the fellowship. The DHS Scholarship and Fellowship Program is administered by the Oak Ridge Institute for Science and Education (ORISE) through an interagency agreement between the US Department of Energy (DOE) and DHS. ORISE is managed by Oak Ridge Associated Universities (ORAU) under DOE Contract DE- AC05-06OR23100.}, pages = {79460K}, doi = {10.1117/12.881270}, author = {L. Mishchenko and B.Hatton. I.B. Burgess and S. David and K. Sandhage and Aizenberg, J.} } @article {837111, title = {Comment in the Nature Special \“What lies ahead.\”}, journal = {Nature}, volume = {469}, year = {2011}, pages = {23-25}, author = {Aizenberg, J.} } @article {837271, title = {Control of bacterial biofilm growth on surfaces by nanostructural mechanics and geometry}, journal = {Nanotechnology}, volume = {22}, year = {2011}, note = {We thank Dr. Yunrong (Win) Chai, Dr. Sigolene Lecuyer and Anna Wang for the biological techniques. The work was supported by the Office of Naval Research (Award No. N000141110641) and BASF Advanced Research Initiative at Harvard University.}, pages = {494007}, doi = {doi:10.1088/0957-4484/22/49/494007}, author = {A. K. Epstein and A. I. Hochbaum and Kim, P. and and J. Aizenberg} } @article {836836, title = {Controlling the Stability and Reversibility of Micropillar Assembly by Surface Chemistry.}, journal = {J. Am. Chem. Soc.}, volume = {133}, year = {2011}, note = {This work was supported by the DOE under Award DE-SC0005247. We acknowledge the use of the facilities at the Harvard Center for Nanoscale Systems supported by NSF Award No. ECS-0335765. We thank Prof. L. Mahadevan for insightful discussions and Dr. A. Grinthal for support with the manuscript preparation. M.M. acknowledges the partial financial assistance by the Marubun Research Promotion Foundation.}, pages = {5545{\textendash}5553}, doi = {10.1021/ja200241j}, author = {M. Matsunaga and Aizenberg, M. and and J. Aizenberg} } @article {837251, title = {Direct Writing and Actuation of Three-Dimensionally Patterned Hydrogel Pads on Micropillar Supports}, journal = {Angew. Chem. Int. Ed}, volume = {123}, year = {2011}, note = {We thank Dr. M. Aizenberg for discussions. This work was supported by the National Institute for Nano Engineering (NINE) program at Sandia National Laboratories; U.S. Department of Energy, Office of Basic Energy Sciences, and the Division of Materials Science and Engineering, grants DE-SC0005247 (respon- sive hydrogel actuation systems), DE-FG02-02-ER15368 (multi- photon lithography capabilities), and the Air Force Office of Scientific Research, grants 9550-10-1-0054 (hybrid materials and devices displaying a symbiotic relationship between the biotic and abiotic components), and FA9550-09-1-0669-DOD35CAP (respon- sive optics). Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States DOE{\textquoteright}s NNSA under contract DE-AC04-94AL85000. B.K. gratefully acknowledges the Sandia National Laboratories Truman Fellowship in National Security Science and Engineering and the Laboratory Directed Research and Development program for support. L.D.Z. thanks the Department of Defense for support through the National Defense Science and Engineering Graduate Fellowship Program, as well as the National Science Foundation for support through the Graduate Research Fellowship Program. M.K. acknowledges the Alexander von Humboldt-Foundation for support through a Feodor Lynen Research Fellowship.}, doi = {10.1002/ange.201102975}, author = {L. D. Zarzar and Kim, P. and Kolle, M. and C. J. Brinker and Aizenberg, J. and and B. Kaehr} } @article {837246, title = {Encoding complex wettability patterns in chemically functionalized 3D photonic crystals}, journal = {J. Am. Chem. Soc.}, volume = {133}, year = {2011}, note = {We thank Dr. W. Noorduin, Dr. T. S. Wong and Dr. P. Kim for enlightening discussions. This work was supported by the Air Force Office of Scientific Research Award $\#$ FA9550-09-1-0669-DOD35CAP. I.B.B. acknowledges support from the Natural Sciences and Engineering Research Council of Canada through the PGS-D program. L.M. acknowledges fellowship support from the Department of Homeland Security (DHS) administered by the Oak Ridge Institute for Science and Education (ORISE) through an interagency agreement between the US Department of Energy (DOE) and DHS under DOE Contract DE-AC05-06OR23100. Electron microscopy was performed at Harvard{\textquoteright}s Center for Nanoscale Systems.}, pages = {12430-12432}, doi = {10.1021/ja2053013}, author = {Burgess, I.B. and L. Mishchenko and B.D. Hatton and Kolle, M. and Loncar, M. and Aizenberg, J.} } @proceedings {837311, title = {Environmentally responsive active optics based on hydrogel-actuated deformable mirror arrays}, volume = {7927}, year = {2011}, note = {This work was supported by the Air Force Office of Scientific Research (Award Number: FA9550-09-1-0669- DOD35CAP). This work was carried out in part through the use of MIT{\textquoteright}s Microsystems Technology Laboratories, Cornell NanoScale Facility (CNF), and Harvard{\textquoteright}s Center for Nanoscale Systems (CNS), which is supported by the National Science Foundation under award number EBCasSe-0335765.}, pages = {792705}, doi = {10.1117/12.879034}, author = {Kim, P. and L. D. Zarzar and Khan, M. and Aizenberg, M. and Aizenberg, J.} } @article {837091, title = {Growth of polygonal rings and wires of CuS on structured surfaces.}, journal = {Cryst. Eng. Comm.}, volume = {13}, year = {2011}, note = {

We would like to thank Dr Michael Aizenburg for helpful discus- sions. Y. V. would like to thank Mary Fieser Postdoctoral Fellow- ship. This work was supported by the Nanoscale Science and Engineering Center (NSEC) (NSF-PHY06-46094). E. M. F. thanks the NSF UNM/Harvard PREM grant.

}, pages = {1077-1080}, doi = {10.1039/C0CE00499E}, author = {Vasquez, Y. and E. M. Fenton and V. F. Chernow and and J. Aizenberg} } @article {837241, title = {Hydrogel-Actuated Integrated Responsive Systems (HAIRS): Moving towards Adaptive Materials}, journal = {Current Opinion in Solid State \& Materials Science}, volume = {15}, year = {2011}, note = {This work was supported by the US Department of Energy, Of- fice of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award $\#$DE-SC0005247 (design and fabrication of HAIRS, HAIRS in liquid); by US Army Research Office Multidisci- plinary University Research Initiative (ARO/MURI) under Award $\#$W911NF-04-1-0476 (STEPS); by US Air Force Office of Scientific Research Multidisciplinary University Research Initiative (AFOSR/ MURI) under Award $\#$FA9550-09-1-0669 (directional actuation and optical properties).}, pages = {236-245}, doi = {10.1016/j.cossms.2011.05.004}, author = {Kim, P. and L. D. Zarzar and He, X. and Grinthal, A. and Aizenberg, J.} } @article {837266, title = {Inhibitory Effects of D-Amino Acids on Staphylococcus aureus Biofilm Development}, journal = {J. Bacteriology}, volume = {193}, year = {2011}, note = {We thank D. A. Weitz and the Harvard Materials Research and Engineering Center (DMR-0213805) for the use of their confocal imaging facilities and M. Gilmore for strains MN8, NCTC 10833, and RN4220. I.K.-G. is a postdoctoral fellow of the Human Frontier Science Program. This work was supported by NIH grants to R.K. (GM58213) and R.L. (GM18546), as well as grants from the BASF Advanced Research Initiative at Harvard University to J.A., R.K., and R.L.}, pages = {5616-5622}, doi = {10.1128/JB.05534-11}, author = {A. I. Hochbaum and I. Kolodkin-Gal and L. Foulston and Kolter, R. and Aizenberg, J. and and R. Losick} } @article {837141, title = {Mechanism of nanostructure movement under an electron beam and its application in patterning.}, journal = {Physical Review B}, volume = {83}, year = {2011}, note = {This work was supported by the Kavli Institute for Bionano Science and Technology at Harvard University, the Materials Research Science and Engineering Center under NSF Award No. DMR-0820484 and the NSF Award No. DMS-0907985. We acknowledge the use of the facilities at the Harvard Center for Nanoscale Systems supported by NSF Award No. ECS-0335765. A.S. was supported by a Marie Curie International Outgoing Fellowship within the 7th European Community Framework Programme.}, pages = {235438-1 - 235438-6}, doi = {10.1103/PhysRevB.83.235438}, author = {A. Seminara and B. Pokroy and S. H. Kang and M.P. Brenner and and J. Aizenberg} } @article {837261, title = {Meniscus Lithography: Evaporation-Induced Self-Organization of Pillar Arrays into Moire Patterns}, journal = {Phys. Rev. Lett.}, volume = {107}, year = {2011}, note = {This work was supported by the AFOSR under Grant No. FA9550{\textendash}09-1{\textendash}0669-DOD35CAP and by the Materials Research Science and Engineering Center under NSF Grant No. DMR-0820484. We acknowledge the use of the facilities at the Harvard Center for Nanoscale Systems supported by NSF Grant No. ECS-0335765. We thank Professor L. Mahadevan and Dr. Philseok Kim for helpful discussions.}, pages = {177802}, doi = {10.1103/PhysRevLett.107.177802}, author = {S. H. Kang and N. Wu and Grinthal, A. and and J. Aizenberg} } @article {837101, title = {Patterning the Tips of Optical Fibers with Metallic Nanostructures Using Nanoskiving.}, journal = {Nano Lett.}, volume = {11}, year = {2011}, note = {This research was supported by the National Science Founda- tion under award PHY-0646094 and by the Office of Naval Research under award N0014-10-1-0942. F.C. acknowledges support by DOD/DARPA under Contract Award No. HR N66001-10-1-4008-DOD. J.A. acknowledges support by the AFOSR under award FA9550-09-1-0669-DOD35CAP. M.A.K. is supported by a graduate research fellowship from the National Science Foundation. The authors used the shared facilities supported by the NSF under NSEC (PHY-0117795 and PHY- 0646094) and MRSEC (DMR-0213805 and DMR-0820484). This work was performed in part using the facilities of the Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Infrastructure Network (NNIN), which is supported by the National Science Foundation under NSF Award No. ECS-0335765. CNS is part of the Faculty of Arts and Sciences at Harvard University.}, pages = {632{\textendash}636}, doi = {10.1021/nl103730g}, author = {D. Lipomi and Martinez, R. and M. Kats and S. H. Kang and Kim, P. and Aizenberg, J. and F. Capasso and G. Whitesides} } @article {837286, title = {Predictive Model for Ice Formation on Superhydrophobic Surfaces}, journal = {Langmuir}, volume = {27}, year = {2011}, note = {This work was funded in part by DARPA (award number HR0011-08-C-0114). Lidiya Mischchenko thanks the U.S. Department of Homeland Security (DHS) Scholarship and Fellowship Program for financial support.}, pages = {14143{\textendash}14150}, doi = {10.1021/la200816f}, author = {V. Bahadur and L. Mishchenko and Hatton, B. and J. A. Taylor and Aizenberg, J. and and T. Krupenkin} } @article {837071, title = {Assembly of large-area, highly ordered, crack-free inverse opal films}, journal = {Proc. Nat. Acad. Sci. USA}, volume = {107}, year = {2010}, note = {This project was supported by the Office of Naval Re- search under Award N00014-07-1-0690-DOD35CAP and by the Air Force Office of Scientific Research under Award FA9550-09-1-0669-DOD35CAP. The work was performed in part at the Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Infrastructure Network (NNIN), which is sup- ported by the National Science Foundation under Award ECS-0335765. L.M. thanks the US Department of Homeland Security (DHS) for the fellow- ship. The DHS Scholarship and Fellowship Program is administered by the Oak Ridge Institute for Science and Education (ORISE) through an interagency agreement between the US Department of Energy (DOE) and DHS. ORISE is managed by Oak Ridge Associated Universities (ORAU) under DOE Contract DE-AC05-06OR23100.}, pages = {10354-10359}, author = {Hatton, B. and L. Mishchenko and S. Davis and K. H. Sandhage and Aizenberg, J.} } @article {837076, title = {Bacteria Pattern Spontaneously on Periodic Nanostructure Arrays}, journal = {Nano Lett.}, volume = {10}, year = {2010}, note = {A.I.H. thanks Dr. Win Chai, Dr. Moshe Shemesh, Dr. Hera Vlamakis, Professor Roberto Kolter, and Professor Richard Losick for use of their facilities, access to various bacterial strains, and helpful discussions. The authors also thank BASF for funding.}, pages = {3717-3721}, author = {A. I. Hochbaum and Aizenberg, J.} } @proceedings {837121, title = {Biomimetic Nanostructured Surfaces with Designer Mechanics and Geometry for Broad Applications}, volume = {1236E}, year = {2010}, note = {We would like to thank Prof. J. J. Vlassak for the use of the 4-point flexure apparatus. This work was partially supported by the Materials Research Science and Engineering Center (MRSEC) of the National Science Foundation under NSF Award Number DMR-0213805.}, pages = {1236-SS09-07}, author = {A. K. Epstein and and J. Aizenberg} } @article {837086, title = {Control of Shape and Size of Nanopillar Assembly by Adhesion-Mediated Elastocapillary Interaction.}, journal = {ACS Nano}, volume = {4}, year = {2010}, note = {This work was partially supported by the Materials Research Science and Engineering Center under NSF Award No. DMR-0820484. We acknowledge the use of the facili- ties at the Harvard Center for Nanoscale Systems supported by NSF Award No. ECS-0335765. We thank Dr. Alison Grinthal for her help to prepare the manuscript. S.H.K. thanks Drs. Ning Wu and Alison Grinthal for helpful discussions.}, pages = {6323{\textendash}6331}, doi = {10.1021/nn102260t}, author = {S. H. Kang and B. Pokroy and L. Mahadevan and Aizenberg, J.} } @article {837096, title = {Design of Ice-free Nanostructured Surfaces Based on Repulsion of Impacting Water Droplets.}, journal = {ACS Nano}, volume = {4}, year = {2010}, note = {Acknowledgment. We would like to thank L. Stirling and A. Grinthal for their valuable contribution. This work was funded in part by DARPA (Award Number HR0011-08-C-0114) and the Wyss Institute for Biologically Inspired Engineering. L. Mish- chenko thanks the U.S. Department of Homeland Security (DHS) Scholarship and Fellowship Program for financial support.}, pages = {7699{\textendash}7707}, doi = {10.1021/nn102557p}, author = {L. Mishchenko and Hatton, B. and V. Bahadur and J. A. Taylor and T. Krupenkin and Aizenberg, J.} } @article {837061, title = {Fabrication and Replication of Arrays of Single- or Multi-Component Nanostructures by Replica Molding and Mechanical Sectioning}, journal = {ACS Nano}, volume = {4}, year = {2010}, note = {This research was supported by the Na- tional Science Foundation under award PHY-0646094. F.C. ac- knowledges a DOD/DARPA Contract Award No. HR 0011-06-1- 0044. The authors used the shared facilities supported by the NSF under MRSEC (DMR-0213805 and DMR-0820484). This work was performed in part using the facilities of the Center for Nano- scale Systems (CNS), a member of the National Nanotechnology Infrastructure Network (NNIN), which is supported by the Na- tional Science Foundation under NSF Award No. ECS-0335765. CNS is part of the Faculty of Arts and Sciences at Harvard Univer- sity. D.J.L. acknowledges a Graduate Fellowship from the Ameri- can Chemical Society, Division of Organic Chemistry, sponsored by Novartis. The authors acknowledge Romain Blanchard and Benjamin Wiley for helpful discussions, Ludovico Cademartiri for synthesizing the PbS nanocrystals, and Christian Pflugl for assis- tance with the optical setup and general advice.}, pages = {4017-4026}, author = {D. Lipomi and M. Kats and Kim, P. and S. H. Kang and Aizenberg, J. and F. Capasso and G. M. Whitesides} } @article {837036, title = {A kinetic model of the transformation of a micropatterned amorphous precursor into a porous single crystal}, journal = {Acta Biomater}, volume = {6}, year = {2010}, pages = {1001{\textendash}1005}, author = {P. Fratzl and F. D. Fischer and J. Svoboda and Aizenberg, J.} } @article {837066, title = {Low-Temperature Synthesis of Nanoscale Silica Multilayers {\textendash} Atomic Layer Deposition in a Test Tube}, journal = {J. Mat. Chem}, volume = {20}, year = {2010}, note = {This project was supported by the Office of Naval Research under Award N00014-07-1-0690-DOD35CAP.}, pages = {6009-6013}, author = {Hatton, B. and V. Kitaev and D. Perovic and G. Ozin and Aizenberg, J.} } @article {837041, title = {Microbristle in gels: Toward all-polymer reconfigurable hybrid surfaces}, journal = {Soft Matter}, volume = {6}, year = {2010}, note = {This project was supported by the Air Force Office of Scientific Research under award number FA9550-09-1-0669-DOD35CAP, by the MRSEC program of the National Science Foundation under award number DMR-082048 and by the WYSS Institute for Biologically Inspired Engineering at Harvard University. The work was performed in part at the Center for Nanoscale Systems (CNS) at Harvard, which is supported by the National Science Foundation under award number ECS-0335765. We thank Alexander E. Epstein for the help in the four-point flexure test.}, pages = {750-755}, author = {Kim, P. and L. D. Zarzar and X. Zhao and A. Sidorenko and Aizenberg, J.} } @article {837051, title = {New nanofabrication strategies: Inspired by biomineralization}, journal = {MRS Bull}, volume = {35}, year = {2010}, note = {I would like to acknowledge G. Whitesides from Harvard University and D. Muller from Bell Labs for their contribu- tions to biomimetic crystal engineering; L. Addadi and S. Weiner from the Weizmann Institute of Science, G. Hendler from the L.A. Museum of Natural History, and S. Yang from Bell Labs for their contri- bution to the biomicrolenses project; T. Krupenkin and A. Sidorenko from Bell Labs and P. Fratzl from MPI for their con- tribution to the study of actuation and dynamic structures; and L. Mahadevan from Harvard for his contributions to the study of chiral self-assembly. I would like to thank my postdocs B. Hatton, B. Pokroy, Y. Han, and P. Kim and my former and current students, J. Weaver, S. Kang, L. Zarzar, A. Epstein, L. Mishchenko, M. Persson Gulda, M. Thanawala, L. Wysocky, A. Briseno, C. Sweeney, T. Holmes, and S. Krout.}, pages = {323-330}, author = {Aizenberg, J.} } @article {837081, title = {Sonication-assisted synthesis of large, high-quality mercury-thiolate single crystals directly from liquid mercury}, journal = {J. Am. Chem. Soc,}, volume = {132}, year = {2010}, note = {We thank O. Paris, S. Siegel, and C. Li for their help during synchrotron diffraction experiments (BESSY II, Helmholtz-Zentrum Berlin, Germany). Some of the supporting powder diffraction measurements were performed at the 11BM beamline of the APS. This work was partially supported by the MRSEC program of the NSF under award DMR-0820-48 and partially by the B. and G. Greenberg (Ottawa) research fund (via the Technion). B.P. is currently a Horev Fellow in the framework of the Leaders in Science Program at the Israel Institute of Technology.}, pages = {14355{\textendash}14357}, doi = {10.1021/ja1056449}, author = {B. Pokroy and B. Aichmayer and A. S. Schenk and B. Haimov and S. H. Kang and P. Fratzl and Aizenberg, J.} } @article {837056, title = {Two-parameter sequential adsorption model applied to microfiber clustering}, journal = {Soft Matter,}, volume = {6}, year = {2010}, note = {J. P. thanks B. Pokroy and S. H. Kang for guidance in con- ducting the experiments, F. Gibaud for use of his pattern recognition program and all three for insightful discussions. Work by J. P. and D. R. N. supported by the National Science Foundation through a Harvard University Materials Research Science and Engineering Center Grant DMR-0820484 and through Grant DMR-0654191. Work by J. A. supported through MRSEC grant DMR-0820484 as well.}, pages = {2421-2434}, author = {J. Paulose and D. R. Nelson and Aizenberg, J.} } @article {837046, title = {Unifying Design Strategies in Demosponge and Hexactinellid Skeletal Systems}, journal = {J. Adhesion}, volume = {86}, year = {2010}, note = {We thank Frank Zok, J. Herbert Waite, Shane Anderson, Nemil Vora, Corey Hardin, Amy Butros, and Armand Kuris for helpful suggestions. DK and NV were supported by a University of California, Riverside Undergraduate Research Grant ($\#$A01009-07431-40-43). JCW and DEM were supported by grants from NASA (NAG1-01-003 and NCC-1-02037); the Institute for Collaborative Biotechnologies, Army Research Office (DAAD19-03D-0004); the NOAA National Sea Grant College Program, U.S. Department of Commerce (NA36RG0537, Project R=MP-92); and the MRSEC Program of the National Science Foundation (DMR-00-8034). PF acknowledges support by the Max Planck Research Award from the Alexander von Humboldt Foundation. BFC acknowledges support from the U.S. National Science Foundation (grant CBET-0829182).}, pages = {72-95}, author = {J. C. Weaver and G. W. Milliron and P. Allen and A. Miserez and A. Rawal and J. Garay and P. J. Thurner and J. Seto and B. Mayzel and L. Jon Friesen and B. F. Chmelka and P. Fratzl and Aizenberg, J. and Y. Dauphin and D. Kisailus and D. E. Morse} } @article {968836, title = {Biological and Biomimetic Materials}, journal = {Adv. Mater.}, volume = {21}, year = {2009}, pages = {387-388}, author = {Aizenberg, J and P. Fratzl} } @article {837026, title = {Crystallization of Malonic and Succinic Acids on SAMs: Toward the General Mechanism of Oriented Nucleation on Organic Monolayers}, journal = {Langmuir}, volume = {25}, year = {2009}, note = {J.A. and V.F.C. thank the Radcliffe Institute for Advanced Studies for support. B.P. extends his gratitude to the Fulbright Visiting Scholar Program. This work was partially supported by the MRSEC program of the National Science Foundation under award number DMR-0820484.}, pages = {14002-14006}, author = {B. Pokroy and V. F. Chernow and Aizenberg, J.} } @article {837021, title = {Droplet Mixing Using Electrically Tunable Superhydrophobic Nanostructured Surfaces}, journal = {Microfluid. Nanofluid.}, volume = {7}, year = {2009}, pages = {137{\textendash}140}, author = {E. N. Wang and M. A. Bucaro and J. A. Taylor and P. Kolodner and Aizenberg, J. and T. Krupenkin} } @proceedings {837301, title = {An Evaporative Co-assembly Method for Highly-Ordered Inverse Opal Films}, volume = {7205}, year = {2009}, pages = {72050-1}, doi = {10.1117/12.809656}, author = {Hatton, B. and L. Mishchenko and R. Norwood and S. Davis and K. Sandhage and Aizenberg, J.} } @article {837006, title = {Fabrication of Bio-Inspired Actuated Nanostructures with Arbitrary Geometry and Stiffness}, journal = {Adv. Mater.}, volume = {21}, year = {2009}, note = {We would like to thank Prof. J. J. Vlassak and H. Li for the use of the four-point flexure apparatus and Prof. G. M. Whitesides and Dr. M. Reches for access to their equipment during the construction of J.A.{\textquoteright}s laboratory. We thank Dr. A. Taylor for the fabrication of Si nanostructures. B.P. would like to extend his gratitude to the Fulbright Visiting Scholar Program for financial support. This work was partially supported by the Materials Research Science and Engineering Center (MRSEC) of the National Science Foundation under NSF Award Number DMR-0213805. Supporting Information is available online from Wiley InterScience or from the author. This article is part of a special issue on Biomaterials.}, pages = {463-469}, author = {B. Pokroy and A. K. Epstein and M. C. M. Persson-Gulda and Aizenberg, J.} } @article {837031, title = {Mechanism of Calcite Co-Orientation in the Sea Urchin Tooth}, journal = {J. Am. Chem. Soc.}, volume = {131}, year = {2009}, note = {WethankLiaAddadiandSteveWeinerfor discussions and comments about the manuscript. We also thank Paul Voyles for tripod polishing. This work was supported by DOE award DE-FG02-07ER15899, NSF award CHE-0613972, and UW- Vilas and Hamel Awards to PUPAG. The experiments were performed at the ALS, supported by DOE under contract DE-AC02- 05CH11231.}, pages = {18404{\textendash}18409}, author = {C. E. Killian and R A. Metzler and Y. Gong and I. C. Olson and Aizenberg, J. and Y. Politi and F. H. Wilt and A. Scholl and A. Young and A. Doran and M. Kunz and N. Tamura and S. N. Coppersmith and P.U.P.A. Gilbert} } @article {837011, title = {Self-Organization of a Mesoscale Bristle into Ordered, Hierarchical Helical Assemblies}, journal = {Science}, volume = {323}, year = {2009}, note = {This work was partially supported by the Materials Research Science and Engineering Center under NSF award no. DMR-0213805. We acknowledge the use of the facilities at the Harvard Center for Nanoscale Systems supported by NSF award no. ECS-0335765. B.P. is grateful to the Fulbright Visiting Scholar Program for financial support.}, pages = {237-240}, author = {B. Pokroy and S. H. Kang and L. Mahadevan and Aizenberg, J.} } @article {837016, title = {Tunable Liquid Optics: Electrowetting-Controlled Liquid Mirrors Based on Self-Assembled Janus Tiles}, journal = {Langmuir}, volume = {25}, year = {2009}, note = {We thank Ben Hatton, Evelyn Wang, and Todd Salamon for enlightening discussions and technical assistance. Also appreciated was the processing support from the New Jersey Nanotechnology Consortium.}, pages = {3876-3879}, author = {M. Bucaro and P. Kolodner and J. A. Taylor and A. Sidorenko and Aizenberg, J. and T. Krupenkin} } @article {836991, title = {Calcium Carbonate Storage in Amorphous Form and Its Template-Induced Crystallization}, journal = {Chem. Mater.}, volume = {20}, year = {2008}, note = {We thank Dongbo Wang of Virginia Tech for the Raman spectroscopy measurement of ACC and calcite. This work was performed in part under the auspices of the U.S. Department of Energy by Lawrence Livermore National Labo- ratory under Contract DE-AC52-07NA27344.}, pages = {1064-1068}, author = {T. Y.-J. Han and Aizenberg, J.} } @article {837001, title = {Controlled Switching of the Wetting Behavior of Biomimetic Surfaces with Hydrogel-Supported Nanostructures}, journal = {invited paper, J. Mater. Chem.}, volume = {18}, year = {2008}, note = {This work was partially supported by the Nanoscale Science and Engineering Center (NSEC) of the National Science Foundation under NSF Award Number PHY-0646094.}, pages = {3841-3846}, author = {A. Sidorenko and T. Krupenkin and Aizenberg, J.} } @article {836996, title = {Effects of Laminate Architecture on Fracture Resistance of Sponge Biosilica: Lessons from Nature}, journal = {Adv. Funct. Mater.}, volume = {18}, year = {2008}, note = {We thank Michael J. Porter, Garrett W. Milliron and Amy Butros for assistance and helpful discussions and B. Richer de Forges, IRD, Noum \&$\#$769;ea, New Caledonia, for collecting the giant spicules of Mono- rhaphis chuni used in this study. AM acknowledges an advanced researcher fellowship from the Swiss National Science Foundation (PA002{\textendash}113176/1). Additionally, AM and FWZ were supported by a grant from the Bioengineering Research Partnership Program, National Institutes of Health (NIHR01DE014672). JCW and DEM were supported by grants from NASA (NAG1-01-003 and NCC-1-02037); the Institute for Collaborative Biotechnologies, Army Research Office (DAAD19-03D-0004); the NOAA National Sea Grant College Pro- gram, U.S. Department of Commerce (NA36RG0537, Project R/ MP-92); and the MRSEC Program of the National Science Foundation (DMR-00-8034). AM and JCW contributed equally to this work.}, pages = {1-8}, author = {A. Miserez and J. C. Weaver and P. J. Thurner and Aizenberg, J. and Y. Dauphin and P. Fratzl and D. E. Morse and F. W. Zok} } @inbook {837126, title = {Self-Assembled Monolayers as Templates for Inorganic Crystallization: A Bio-Inspired Approach}, year = {2008}, pages = {17 - 32}, publisher = {Dordrecht, Netherlands}, organization = {Dordrecht, Netherlands}, address = {Springer WB/Nato Publishing Unit}, author = {Aizenberg, J.}, editor = {J.J. Novoa} } @article {836986, title = {Calcite Shape Modulation through the Lattice Mismatch between the Self-Assembled Monolayer Template and the Nucleated Crystal Face}, journal = {CrystEngComm}, volume = {9}, year = {2007}, note = {We would like to thank Prof. E. Zolotoyabko and Dr A. A. Chernov for very helpful discussions. B.P. would like to extend his gratitude to the Fulbright Visiting Scholar Program for financial support. This work was partially supported by the Office of Naval Research (ONR) Award $\#$N00014-05-1-0909. J.A. is the incumbent of the Gordon McKay Professor of Materials Science chair and the Susan S. and Kenneth L. Wallach Professor chair.}, pages = {1219-1225}, author = {B. Pokroy and Aizenberg, J.} } @article {836981, title = {Hierarchical Assembly of the Siliceous Skeletal Lattice of the Hexactinellid Sponge Euplectella aspergillum}, journal = {J. Struct. Biol.}, volume = {158}, year = {2007}, note = {We thank Micha Ilan, Garrett W. Milliron, and Amy Butros for their help and discussions. JCW and DEM were supported by Grants from NASA (NAG1-01-003 and NCC-1-02037), the Institute for Collaborative Biotechnologies through Grant DAAD19-03D-0004 from the Army Research Office, and the NOAA National Sea Grant College Program, U.S. Department of Commerce (NA36RG0537, Project R/MP-92) through the California Sea Grant College System and the MRSEC Program of the National Science Foundation under award$\#$ DMR- 00-8034 to the UCSB Materials Research Laboratory. GEF and PKH were supported by Grants from National Institutes of Health under Award GM65354, NASA University Research, Engineering and Technology Institute on Bio-inspired Materials under Award No. NCC-1-02037, and a research agreement with Veeco $\#$SB030071. GEF thanks the Austrian Academy of Sciences through a DOC fellowship. JA was supported in part by the Binational US-Israel Science Foundation grant.}, pages = {93{\textendash}106}, author = {J. C. Weaver and Aizenberg, J. and G. E. Fantner and D. Kisailus and A. Woesz and P. Allen and K. Fields and M. J. Porter and F. W. Zok and P. K. Hansma and P. Fratzl and D. E. Morse} } @article {836976, title = {Reversible Switching of Hydrogel-Actuated Nanostructures into Complex Micropatterns}, journal = {Science}, volume = {315}, year = {2007}, note = {We thank P. Kolodner, J. Weaver, I. Luzinov, and I. Sokolov for fruitful discussions. We thank R. Smith and N. Lippa for technical assistance. This work was supported in part by the Office of Naval Research, award N00014-05-1-0909.}, pages = {487-490}, author = {A. Sidorenko and T. Krupenkin and A. Taylor and P. Fratzl and Aizenberg, J.} } @proceedings {837151, title = {Accelerated Chemical Reactions for Lab-on-a-Chip Applications Using Electrowetting-Induced Droplet Self-Oscillations}, volume = {915}, year = {2006}, pages = {0915-R06-10}, author = {Aizenberg, J. and T. Krupenkin and P. Kolodner} } @article {836966, title = {Micromechanical Properties of Biological Silica in Skeletons of Deep-Sea Sponges}, journal = {J. Mater. Res.}, volume = {21}, year = {2006}, pages = {2068-2078}, author = {A. Woesz and J. C. Weaver and M. Kazanci and Y. Dauphin and D. E. Morse and Aizenberg, J. and P. Fratzl} } @proceedings {837146, title = {Selective Trapping of Nanoparticles on Adaptive, Topographic Surfaces}, volume = {94}, year = {2006}, pages = {852}, author = {Zhang, Y. and S. Qin and J. A. Taylor and Aizenberg, J. and Yang, S.} } @article {836971, title = {Tunable Microfluidic Optical Devices with an Integrated Microlens Array}, journal = {J. Micromech. Microeng}, volume = {16}, year = {2006}, pages = {1660-1666}, author = {K.-S. Hong and J. Wang and A. Sharonov and D. Chandra and Aizenberg, J. and Yang, S.} } @article {836951, title = {Bio-Inspired Approach to Controlled Crystallization at the Nanoscale}, journal = {Bell Labs Technical Journal}, volume = {10}, year = {2005}, pages = {129-141}, author = {Aizenberg, J.} } @proceedings {837181, title = {Controlled Synthesis of Micropatterned Single Crystals via Amorphous-to-Crystalline Transition Induced by Polymer-Modified 3D Templates}, volume = {325}, year = {2005}, author = {Aizenberg, J.} } @proceedings {837171, title = {Effects of Magnesium Ions on Crystallization and Morphogenesis of Oriented Calcite Crystals Templated by Organic Surfaces}, year = {2005}, pages = {212-215}, author = {Y.-J. Han and Aizenberg, J.} } @article {836926, title = {Functional Biomimetic Microlens Arrays With Integrated Pores}, journal = {Adv. Mater.}, volume = {17}, year = {2005}, pages = {435-438}, author = {Yang, S. and G. Chen and Megens, M. and C. K. Ullal and Y.-J. Han and R. Rapaport and E. L. Thomas and Aizenberg, J.} } @article {836936, title = {Microlens Arrays with Integrated Pores as a Multipattern Photomask}, journal = {Appl. Phys. Lett}, volume = {86}, year = {2005}, pages = {201121}, author = {Yang, S. and C. K. Ullal and E. L. Thomas and G. Chen and Aizenberg, J.} } @article {836961, title = {Multifunctional Biomimetic Microlens Arrays with Integrated Pores}, journal = {Nano Today}, volume = {12}, year = {2005}, pages = {40-46}, author = {Yang, S. and Aizenberg, J.} } @proceedings {837161, title = {Multifunctional Biomimetic Microlens Arrays with Integrated Pores}, year = {2005}, pages = {164}, author = {Yang, S. and Aizenberg, J.} } @inbook {837166, title = {Nanomechanics of Biological Single Crystals: The Role of Intracrystalline Proteins}, year = {2005}, pages = {99-108}, publisher = {Springer}, organization = {Springer}, address = {Dordrecht, Netherlands}, author = {Aizenberg, J.}, editor = {T.-J. Chuang and P. M. Anderson and M.-K. Wu and S. Hsieh} } @inbook {837176, title = {Optical Fibers of Deep Sea Sponges}, year = {2005}, publisher = {McGraw-Hill}, organization = {McGraw-Hill}, author = {A. Yablon and Aizenberg, J.} } @article {836946, title = {Orientation and Mg Incorporation of Calcite Grown on Functionalized Self-Assembled Monolayers: A Synchrotron X-ray Study}, journal = {Cryst. Growth Des.}, volume = {5}, year = {2005}, pages = {2139-2145}, author = {S.-Y. Kwak and E. DiMasi and Y.-J. Han and Aizenberg, J.} } @article {836956, title = {Patterned Growth of Large Oriented Organic Semiconductor Single Crystals on Self-Assembled Monolayer Templates}, journal = {J. Am. Chem. Soc}, volume = {127}, year = {2005}, pages = {12164-12165}, author = {A. L. Briseno and Y.-J. Han and R. A. Penkala and H. Moon and A. J. Lovinger and C. Kloc and Z. Bao and Aizenberg, J.} } @article {836931, title = {Skeleton of Euplectella sp.: Structural Hierarchy from the Nanoscale to the Macroscale}, journal = {Science}, volume = {309}, year = {2005}, pages = {275-278}, author = {Aizenberg, J. and J. C. Weaver and M. S. Thanawala and V. C. Sundar and D. E. Morse and P. Fratzl} } @proceedings {837156, title = {Surface-Induced Recrystallization of Amorphous Calcium Carbonates to Oriented Calcite Crystals}, volume = {873E}, year = {2005}, pages = {K4.10}, author = {Y.-J. Han and Aizenberg, J.} } @article {836941, title = {Synthesis of Photoacid Crosslinkable Hydrogels for the Fabrication of Soft, Biomimetic Microlens Arrays}, journal = {J. Mater.}, volume = {15}, year = {2005}, pages = {4200-4202}, author = {Yang, S. and J. Ford and C. Ruengruglikit and Q. Huang and Aizenberg, J.} } @proceedings {837131, title = {Synthetic Biomimetic Microlens Arrays from Polymers}, volume = {93}, year = {2005}, pages = {133}, author = {Aizenberg, J. and Yang, S.} } @article {836921, title = {Template-Dependent Morphogenesis of Oriented Calcite Crystals in the Presence of Magnesium Ions}, journal = {Angew. Chem. Int. Ed}, volume = {44}, year = {2005}, pages = {2386 - 2390}, author = {Y.-J. Han and L. M. Wysocky and M. Thanawala and T. Siegrist and Aizenberg, J.} } @proceedings {837191, title = {Bio-Inspired Periodic Microlens Arrays with Integrated Pore Structures Created by Multiple-Beam Interference Lithography}, volume = {90}, year = {2004}, pages = {379}, author = {Yang, S. and G. Chen and Megens, M. and C. K. Ullal and Y.-J. Han and R. Rapaport and C. Ruengruglikit and Q. Huang and E. L. Thomas and Aizenberg, J.} } @article {836911, title = {Biological Glass Fibers:~ Correlation between Optical and Structural Properties}, journal = {Proc. Nat. Acad. Sci. USA}, volume = {101}, year = {2004}, pages = {3358-3363}, author = {Aizenberg, J. and V. C. Sundar and A. D. Yablon and J. C. Weaver and G. Chen} } @article {836916, title = {Crystallization in Patterns:~ A Bio-Inspired Approach}, journal = {Adv. Mater.}, volume = {16}, year = {2004}, pages = {1295-1302}, author = {Aizenberg, J.} } @article {836906, title = {Designing Efficient Microlens Arrays:~ Lessons from Nature}, journal = {J. Mater. Chem.}, volume = {14}, year = {2004}, pages = {2066-2072}, author = {Aizenberg, J. and Hendler, G.} } @inbook {837196, title = {Learning From Marine Creatures}, year = {2004}, pages = {151-166}, publisher = {Kluwer Acad. Publ.}, organization = {Kluwer Acad. Publ.}, address = {Netherlands}, author = {Aizenberg, J. and Hendler, G.}, editor = {R. L. Reis and S. Weiner} } @inbook {837206, title = {Multilevel Control of Calcite Crystallization Using Self-Assembled Monolayers}, year = {2004}, pages = {209-214}, publisher = {Tokai Univ. Press}, organization = {Tokai Univ. Press}, address = {Japan}, author = {Aizenberg, J.}, editor = {I. Kobayashi and H. Ozawa} } @article {836901, title = {New Developments in Bio-Related Materials}, journal = {J. Mater. Chem.}, volume = {14}, year = {2004}, pages = {E5-E6}, author = {Aizenberg, J. and J. Livage and S. Mann} } @proceedings {837186, title = {Photonic Crystals Through Interference Lithography: A Level Set Approach}, volume = {EXS-2}, year = {2004}, pages = {179-181}, author = {C. Ullal and M. Maldovan and Yang, S. and G. Chen and Y-J. Han and Aizenberg, J. and R. Rapaport and C. White and E. L. Thomas} } @proceedings {837201, title = {Shape, Size and Morphology Control of Inorganic Crystals With Self-Assembled Monolayers}, volume = {823}, year = {2004}, pages = {115-119}, author = {Y.-J. Han and Aizenberg, J.} } @article {836881, title = {Coexistence of Amorphous and Crystalline Calcium Carbonate in Skeletal Tissues}, journal = {Connect. Tissue Res.}, volume = {44}, year = {2003}, pages = {20-25}, author = {Aizenberg, J. and S. Weiner and L. Addadi} } @article {836871, title = {Direct Fabrication of Large Micropatterned Single Crystals}, journal = {Science}, volume = {299}, year = {2003}, pages = {1205-1208}, author = {Aizenberg, J. and D. A. Muller and J. L. Grazul and D. R. Hamann} } @article {836861, title = {Effect of Magnesium Ions on Oriented Growth of Calcite on Carboxylic Acid Functionalized Self-Assembled Monolayer}, journal = {J. Am. Chem. Soc.}, volume = {125}, year = {2003}, pages = { 4032-4033}, author = {Y.-J. Han and Aizenberg, J.} } @article {836876, title = {Face-Selective Nucleation of Calcite on Self-Assembled Monolayers of Alkanethiols: Effect of the Parity of the Alkyl Chain}, journal = {Angew. Chem. Int. Ed.}, volume = {42}, year = {2003}, pages = {3668-3670}, author = {Y.-J. Han and Aizenberg, J.} } @article {836886, title = {Fiber-Optical Features of a Glass Sponge}, journal = {Nature}, volume = {424}, year = {2003}, pages = {899-900}, author = {V. C. Sundar and A. D. Yablon and J. L. Grazul and M. Ilan and Aizenberg, J.} } @article {836896, title = {Like-Charged Particles at Liquid Interfaces}, journal = {Nature}, volume = {424}, year = {2003}, pages = {1014}, author = {Megens, M. and Aizenberg, J.} } @article {836891, title = {Narrow Features in Metals at the Interfaces Between Different Etch Resists}, journal = {Appl. Phys. Lett.}, volume = {83}, year = {2003}, pages = { 2259-2261}, author = {V. C. Sundar and Aizenberg, J.} } @proceedings {837211, title = {Structural and Initial Optical Characterization of Basalia Spicules in the Glass Sponge Euplectella}, volume = {774}, year = {2003}, pages = {115-119}, author = {V. C. Sundar and J. Grazul and Aizenberg, J.} } @proceedings {837216, title = {Creating Periodic 3D Structures by Multiple-Beam Interference of Visible Laser}, volume = {43}, year = {2002}, pages = {548}, author = {Yang, S. and Megens, M. and Wiltzius, P. and Aizenberg, J.} } @article {836851, title = {Creating Periodic Three-Dimensional Structures by Multibeam Interference of Visible Laser}, journal = {Chem. Mater}, volume = {14}, year = {2002}, pages = {2831-2833}, author = {Yang, S. and Megens, M. and Aizenberg, J. and Wiltzius, P. and P. M. Chaikin and W. B. Russel} } @article {836856, title = {Factors Involved in the Formation of Amorphous and Crystalline Calcium Carbonate:~ A Study of an Ascidian Skeleton}, journal = {J. Am. Chem. Soc.}, volume = {124}, year = {2002}, pages = {32-39}, author = {Aizenberg, J. and G. Lambert and S. Weiner and L. Addadi} } @article {836846, title = {Calcitic Microlenses as Part of the Photoreceptor System in Brittlestars}, journal = {Nature}, volume = {412}, year = {2001}, pages = {819-822}, author = {Aizenberg, J. and Tkachenko, A. and S. Weiner and L. Addadi and Hendler, G.} } @proceedings {837221, title = {Templated crystallization of calcite on patterned self-assembled monolayers}, volume = {620}, year = {2001}, pages = {M4.1.1-10}, author = {Aizenberg, J.} } @article {836841, title = {Patterned Colloidal Deposition Controlled by Electrostatic and Capillary Forces}, journal = {Phys. Rev. Lett.}, volume = {84}, year = {2000}, pages = {2997-3000}, author = {Aizenberg, J. and P. V. Braun and Wiltzius, P.} } @article {836831, title = {Patterned Crystallisation on Self-Assembled Monolayers with Integrated Regions of Disorder}, journal = {J. Chem. Soc. Dalton Trans.}, year = {2000}, pages = {3963-3968}, author = {Aizenberg, J.} } @article {836821, title = {Patterned Crystallization of Calcite in Vivo and in Vitro}, journal = {J. Crystal Growth}, volume = {211}, year = {2000}, pages = {143-148}, author = {Aizenberg, J.} } @article {836826, title = {Ultraviolet Lithography of Self-Assembled Monolayers for Submicron Patterned Deposition}, journal = {Appl. Phys. Lett.}, volume = {77}, year = {2000}, pages = {2406-2408}, author = {S. Friebel and Aizenberg, J. and S. Abad and Wiltzius, P.} } @inbook {837231, title = {On the concept of a single crystal in biomineralization}, year = {1999}, publisher = {Kluwer Acad. Publ.}, organization = {Kluwer Acad. Publ.}, address = {Dordrecht, Netherlands}, author = {L. Addadi and Aizenberg, J. and E. Beniash and S. Weiner} } @article {836811, title = {Control of Nucleation by Patterned Self-Assembled Monolayers}, journal = {Nature}, volume = {398}, year = {1999}, pages = {495-498}, author = {Aizenberg, J. and A. J. Black and G. M. Whitesides} } @proceedings {837226, title = {Engineering the Microenvironment of Crystals Nucleation and Growth Using Micropatterned Polymers}, volume = {81}, year = {1999}, pages = {2-3}, author = {Aizenberg, J. and A. J. Black and G. M. Whitesides} } @article {836806, title = {Oriented Growth of Calcite Controlled by Self-Assembled Monolayers of Functionalized Alkanethiols Supported on Gold and Silver}, journal = {J. Am. Chem. Soc.}, volume = {121}, year = {1999}, pages = {4500-4509}, author = {Aizenberg, J. and A. J. Black and G. M. Whitesides} } @article {836816, title = {Patterning Disorder in Monolayer Resists for the Fabrication of sub-100-nm Structures in Silver, Gold, Silicon, and Aluminum}, journal = {J. Am. Chem. Soc.}, volume = {121}, year = {1999}, pages = {8356-8365}, author = {A. J. Black and K. E. Paul and Aizenberg, J. and G. M. Whitesides} } @article {836791, title = {Controlling Local Disorder in Self-Assembled Monolayers by Patterning the Topography of their Metallic Supports}, journal = {Nature}, volume = {394}, year = {1998}, pages = {868-871}, author = {Aizenberg, J. and A. J. Black and G. M. Whitesides} } @article {836796, title = {Imaging Profiles of Light Intensity in the near field: Applications to Phase-Shift Photolithography}, journal = {Appl. Opt.}, volume = {37}, year = {1998}, pages = {2145-2152}, author = {Aizenberg, J. and J. A. Rogers and K. E. Paul and G. M. Whitesides} } @article {836801, title = {Maskless Photolithography:~ Embossed Photoresist as Its Own Optical Element}, journal = {Appl. Phys. Lett.}, volume = {73}, year = {1998}, pages = {2893-2895}, author = {K. E. Paul and T. L. Breen and Aizenberg, J. and G. M. Whitesides} } @article {836776, title = {Amorphous Calcium Carbonate Transforms into Calcite during Sea Urchin Larval Spicule Growth}, journal = {Proc. R. Soc. Lond. B.}, volume = {264}, year = {1997}, pages = {461-465}, author = {E. Beniash and Aizenberg, J. and L. Addadi and S. Weiner} } @article {836781, title = {Control of Macromolecule Distribution within Synthetic and Biogenic Single Calcite Crystals}, journal = {J. Am. Chem. Soc.}, volume = {119}, year = {1997}, pages = {881-886}, author = {Aizenberg, J. and J. Hanson and T. F. Koetzle and S. Weiner and L. Addadi} } @article {836786, title = {Imaging the Irradiance Distribution in the Optical Near Field}, journal = {Appl. Phys. Let.}, volume = {71}, year = {1997}, pages = {3773-3775}, author = {Aizenberg, J. and J. A. Rogers and K. E. Paul and G. M. Whitesides} } @article {836761, title = {Dynamics and Growth Patterns of Calcareous Sponge Spicules}, journal = {Proc. R. Soc. Lond. B.}, volume = {263}, year = {1996}, pages = {133-139}, author = {M. Ilan and Aizenberg, J. and O. Gilor} } @article {836766, title = {Intracrystalline Macromolecules are Involved in the Morphogenesis of Calcitic Sponge Spicules}, journal = {Connect. Tissue Res.}, volume = {34}, year = {1996}, pages = {255-261}, author = {Aizenberg, J. and M. Ilan and S. Weiner and L. Addadi} } @article {836771, title = {Stabilization of Amorphous Calcium Carbonate by Specialized Macromolecules in Biological and Synthetic Precipitates}, journal = {Adv. Mat.}, volume = {8}, year = {1996}, pages = {222-225}, author = {Aizenberg, J. and G. Lambert and L. Addadi and S. Weiner} } @article {836756, title = {Biologically-Induced Reduction in Symmetry:~ A Study of Crystal Texture of Calcitic Sponge Spicules}, journal = {Chem. Eur. J.}, volume = {7}, year = {1995}, pages = {414-422}, author = {Aizenberg, J. and J. Hanson and T. F. Koetzle and L. Leiserowitz and S. Weiner and L. 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