%0 Journal Article %J Chemical Reviews %D 2022 %T Dilute Alloys based on Au, Ag, or Cu for Efficient Catalysis: from synthesis to active sites %A Jennifer D. Lee %A Jeff B. Miller %A Anna V. Shneidman %A L. Sun %A J. F. Weaver %A Joanna Aizenberg %A J. Biener %A J. A. Boscoboinik %A Amanda C. Foucher %A Anatoly I. Frenkel %A Jessi E. S. van der Hoeven %A Boris Kozinsky %A Nicholas Marcella %A Matthew M. Montemore %A Hio Tong Ngan %A Christopher R. O’Connor %A Cameron J. Owen %A Eric A. Stach %A Robert J. Madix %A Philippe Sautet %A Cynthia M. Friend %B Chemical Reviews %V 122 %G eng %U https://pubs.acs.org/doi/10.1021/acs.chemrev.1c00967 %N 9 %0 Journal Article %J Nature %D 2022 %T Self-regulated non-reciprocal motions in single-material microstructures %A S Li %A Lerch, MM %A Waters, James T. %A Deng, B. %A Martens, Reese S %A Yao, Y. %A Kim, D. %A Bertoldi, K. %A Grinthal, A. %A Balazes, A %A Aizenberg, Joanna %X

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.

 
%B Nature %V 605 %P 76-83 %G eng %N 7908 %0 Journal Article %J Nature Communications %D 2022 %T Decoding reactive structures in dilute alloy catalysts %A Marcella, N %A Lim, J S %A Plonka, A M %A Yan, G %A Owen CJ %A van der Hoeven, JES %A Foucher, AC %A Ngan, HT %A Torrisi, SB %A Marinkovic, NS %A Stach, E.A. %A Weaver, JF %A Aizenberg, J %A Sautet, P %A Kozinsky, B %A Frenkel, A %X

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.

%B Nature Communications %V 13 %P 1-9 %G eng %U https://www.nature.com/articles/s41467-022-28366-w %N 1 %0 Journal Article %J Chemical science %D 2022 %T Mapping blood biochemistry by Raman spectroscopy at the cellular level %A Volkov, V %A McMaster, J %A Aizenberg, J %A Perry, Carole %X

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.

%B Chemical science %V 13 %P 133-140 %G eng %U https://pubs.rsc.org/en/content/articlelanding/2022/SC/D1SC05764B %N 1 %0 Journal Article %J Nature Communications %D 2022 %T Patterned crystal growth and heat wave generation in hydrogels %A Schroeder, TBH %A Aizenberg, J %X

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 45˚C, while slower-crystallizing polymerized solutions produced polycrystalline composites and peaked at 30˚C 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.

%B Nature Communications %V 13 %P 1-11 %G eng %U https://www.nature.com/articles/s41467-021-27505-z %N 1 %0 Journal Article %J Angewandte Chemie International Edition %D 2021 %T Highly Ordered Inverse Opal Structures Synthesized from Shape‐Controlled Nanocrystal Building Blocks %A Han, J.H. %A Shneidman, A.V. %A Kim, DY %A Nicolas, NJ %A van der Hoeven, J %A Aizenberg, M. %A Aizenberg, J %X

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.

%B Angewandte Chemie International Edition %V 61 %G eng %U https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202111048 %0 Journal Article %J Journal of the American Chemical Society %D 2021 %T Spiropyran Photoisomerization Dynamics in Multiresponsive Hydrogels %A Meeks, A %A Lerch, MM %A Schroeder, TBH %A Shastri, A. %A Aizenberg, J %X

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–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–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.

%B Journal of the American Chemical Society %V 144 %P 219 %G eng %U https://pubs.acs.org/doi/abs/10.1021/jacs.1c08778 %N 1 %0 Journal Article %J Bioinspiration & biomimetics %D 2021 %T Bioinspired design and optimization for thin film wearable and building cooling systems %A Grinham, J %A Hancock, MJ %A Kumar, K %A Bechthold, M %A Ingber, DE %A Aizenberg, J %X

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.

%B Bioinspiration & biomimetics %V 17 %P 015003 %G eng %U https://iopscience.iop.org/article/10.1088/1748-3190/ac2f55/meta %N 1 %0 Journal Article %J Micron %D 2021 %T Finite-difference Time-domain (FDTD) Optical Simulations: A Primer for the Life Sciences and Bio-Inspired Engineering %A McCoy DE %A Shneidman AV %A Davis, AL %A Aizenberg, J. %X

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.

%B Micron %V 151 %P 103160 %G eng %U https://reader.elsevier.com/reader/sd/pii/S0968432821001517?token=C3A313DCB1A3C9779A241A4F9B4C2A818CC936DA87D0281483E35F4645C65E29B4D1D0D79CCBEEF775592793CBBB7781&originRegion=us-east-1&originCreation=20220215203155 %0 Journal Article %J Advanced Functional Materials %D 2021 %T On the Origin of Sinter‐Resistance and Catalyst Accessibility in Raspberry‐Colloid‐Templated Catalyst Design %A van der Hoeven, J %A Krämer, S. %A Dussi, S. %A Shirman, T. %A Park, K %A Rycroft, C %A Bell, D %A Friend, C %A Aizenberg, J. %X

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.

%B Advanced Functional Materials %P 2106876 %G eng %U https://onlinelibrary.wiley.com/doi/epdf/10.1002/adfm.202106876 %0 Journal Article %J Advanced Materials %D 2021 %T Controlling Liquid Crystal Orientations for Programmable Anisotropic Transformations in Cellular Microstructures %A S Li %A Librandi, G %A Y Yao %A Richard, A %A Yamamura, A. S %A Aizenberg, J %A Bertoldi, K. %X

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 ”area-specific” 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.

%B Advanced Materials %P 2105024 %G eng %0 Journal Article %J Proceedings of the National Academy of Sciences %D 2021 %T Microscopic origins of the crystallographically preferred growth in evaporation-induced colloidal crystals %A Li, Ling %A Goodrich, Carl %A Yang, Haizhao %A Phillips, Katherine R %A Jia, Zian %A Chen, Hongshun %A Wang, Lifeng %A Zhang, Jinjin %A Liu, Anhua %A Lu, Jianfeng %A Shuai, Jianwei %A Brenner, Michael %A Spaepen, Frans %A Aizenberg, Joanna %X

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.

%B Proceedings of the National Academy of Sciences %V 118 %P e2107588118 %G eng %U https://www.pnas.org/content/118/32/e2107588118.short %N 32 %0 Journal Article %J Proceedings of the National Academy of Sciences %D 2021 %T Microstructural design for mechanical–optical multifunctionality in the exoskeleton of the flower beetle Torynorrhina flammea %A Jia, Zian %A Fernandes, Matheus C. %A Deng, Zhifeng %A Yang, Ting %A Zhang, Qiuting %A Lethbridge, Alfie %A Yin, Jie %A Lee, Jae-Hwang %A Han, Lin %A Weaver, James %A Bertoldi, Katia %A Aizenberg, Joanna %A Kolle, Mathias %A Vukusic, Pete %A Li, Ling %X

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–mechanics–optics relationship of the beetle’s cuticle, opening avenues to investigate biological materials and design photonic materials with robust mechanical performance.

%B Proceedings of the National Academy of Sciences %V 118 %P e2101017118 %G eng %U https://www.pnas.org/content/118/25/e2101017118.short %N 25 %0 Journal Article %J Journal of Catalysis %D 2021 %T Dilute Pd-in-Au alloy RCT-SiO2 catalysts for enhanced oxidative methanol coupling %A Filie, Amanda %A Shirman, Tanya %A Foucher, Alexandre C. %A Stach, Eric A. %A Aizenberg, Michael %A Aizenberg, Joanna %A Friend, Cynthia M %A Madix, Robert J %X

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 (“raspberry colloid templated” (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.

%B Journal of Catalysis %G eng %U https://www.sciencedirect.com/science/article/pii/S0021951721002396 %0 Journal Article %J ACS Catalysis %D 2021 %T Entropic Control of HD Exchange Rates over Dilute Pd-in-Au Alloy Nanoparticle Catalysts %A van der Hoeven, Jessi ES %A Ngan, Hio Tong %A Taylor, Austin %A Eagan, Nathaniel M %A Aizenberg, Joanna %A Sautet, Philippe %A Madix, Robert J %A Friend, Cynthia M %X

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.

%B ACS Catalysis %V 11 %P 6971-6981 %G eng %U https://pubs.acs.org/doi/abs/10.1021/acscatal.1c01400 %0 Journal Article %J Scientific Reports %D 2021 %T Enhanced condensation heat transfer using porous silica inverse opal coatings on copper tubes %A Adera, Solomon %A Naworski, Lauren %A Davitt, Alana %A Mandsberg, Nikolaj %A Shneidman, Anna V %A Jack Alvarenga %A Aizenberg, Joanna %X

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 3–4 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.

%B Scientific Reports %V 11 %P 1-11 %G eng %U https://www.nature.com/articles/s41598-021-90015-x %N 1 %0 Journal Article %J Advanced Materials Interfaces %D 2021 %T Bioinspired Soft Microactuators %A Zhu, Pingan %A Chen, Rifei %A Zhou, Chunmei %A Aizenberg, Michael %A Aizenberg, Joanna %A Wang, Liqiu %X 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 “on” and “off” 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 (20–850 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 2–3 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. %B Advanced Materials Interfaces %V 33 %P 2008558 %G eng %U https://onlinelibrary.wiley.com/doi/full/10.1002/adma.202008558 %N 21 %0 Journal Article %J MOLECULAR THERAPY %D 2021 %T Slippery Liquid-Infused Porous Surfaces (SLIPS) for Cell Deformation Enabling Intracellular Cargo Delivery %A Frost, Isaura M. %A Mendoza, Alexandra %A Chiou, Tzu-Ting %A Wattanatorn, Natcha %A Zhao, Chuanzhen %A Yang, Qing %A Kim, Philseok %A Aizenberg, Joanna %A De Oliveira, Satiro %A Weiss, Paul S. %A Jonas, Steven J %B MOLECULAR THERAPY %V 29 %P 233 %G eng %N 4 %0 Journal Article %J Nature %D 2021 %T Liquid-induced topological transformations of cellular microstructures %A Li, Shucong %A Deng, Bolei %A Alison Grinthal %A Schneider-Yamamura, Alyssa %A Kang, Jinliang %A Martens, Reese S %A Zhang, Cathy T %A Li, Jian %A Yu, Siqin %A Bertoldi, Katia %A Aizenberg, Joanna %X

The fundamental topology of cellular structures—the location, number and connectivity of nodes and compartments—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 ‘zip’ 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–evaporation–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.

%B Nature %V 592 %P 386-391 %G eng %U https://www.nature.com/articles/s41586-021-03404-7 %N 7854 %0 Journal Article %J ACS Applied Materials & Interfaces %D 2021 %T Why Are Water Droplets Highly Mobile on Nanostructured Oil-Impregnated Surfaces? %A Zhang, Chengcheng %A Adera, Solomon %A Aizenberg, Joanna %A Chen, Zhan %X

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—one of the limitations and major concerns of SLIPS.

%B ACS Applied Materials & Interfaces %V 13 %P 15901-15909 %G eng %U https://pubs.acs.org/doi/abs/10.1021/acsami.1c01649 %N 13 %0 Journal Article %J Advanced Healthcare Materials %D 2021 %T Inverse Opal Films for Medical Sensing: Application in Diagnosis of Neonatal Jaundice %A Nicolas, Natalie %A Duffy, Meredith A. %A Hansen, Anne %A Aizenberg, Joanna %X

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.

%B Advanced Healthcare Materials %V 10 %P 2001326 %G eng %U https://onlinelibrary.wiley.com/doi/abs/10.1002/adhm.202001326 %N 4 %0 Journal Article %J Nature Materials %D 2021 %T Mechanically robust lattices inspired by deep-sea glass sponges %A Fernandes, Matheus %A Aizenberg, Joanna %A Weaver, James %A Bertoldi, Katia %X

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’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.

%B Nature Materials %V 20 %P 237-241 %G eng %U https://www.nature.com/articles/s41563-020-0798-1 %N 2 %0 Journal Article %J Proceedings of the National Academy of Sciences %D 2021 %T Designing angle-independent structural colors using Monte Carlo simulations of multiple scattering %A Hwang, Victoria %A Stephenson, Anna %A Barkley, Solomon %A Brandt, Soeren %A Xiao, Ming %A Aizenberg, Joanna %A Manoharan, Vinothan N %X

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—cosmetics or displays, for example—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.

%B Proceedings of the National Academy of Sciences %V 118 %P e2015551118 %G eng %U https://www.pnas.org/content/118/4/e2015551118.short %N 4 %0 Journal Article %J Catalysis Today %D 2021 %T Raspberry colloid-templated approach for the synthesis of palladium-based oxidation catalysts with enhanced hydrothermal stability and low-temperature activity %A Shirman, Tanya %A Toops, Todd J %A Shirman, Elijah %A Shneidman, Anna V %A Liu, Sissi %A Gurkin, Keeve %A Jack Alvarenga %A Lewandowski, Michael %A Aizenberg, Michael %A Aizenberg, Joanna %X

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 °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 — “raspberry” polymeric colloids decorated with catalytic particles — 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 °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 °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.

%B Catalysis Today %V 360 %P 241-251 %G eng %U https://www.sciencedirect.com/science/article/pii/S0920586120301541 %0 Journal Article %J Soft Matter %D 2021 %T Controllable growth of interpenetrating or random copolymer networks %A Chatterjee, Rayan %A Biswas, Santidan %A Yashin, Victor V. %A Aizenberg, Michael %A Aizenberg, Joanna %A Balazs, Anna C %X

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 “seed” 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.

%B Soft Matter %V 17 %P 7177-7187 %G eng %U https://pubs.rsc.org/en/content/articlelanding/2021/SM/D1SM00611H %N 30 %0 Journal Article %J Catalysis Science & Technology %D 2021 %T The dynamic behavior of dilute metallic alloy Pd x Au 1− x/SiO 2 raspberry colloid templated catalysts under CO oxidation %A Filie, Amanda %A Shirman, Tanya %A Aizenberg, Michael %A Aizenberg, Joanna %A Friend, Cynthia M. %A Madix, Robert J. %X

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.

%B Catalysis Science & Technology %P 4072-4082 %G eng %U https://pubs.rsc.org/en/content/articlelanding/2021/CY/D1CY00469G %N 11 %0 Journal Article %J Advanced Materials Interfaces %D 2021 %T Self‐Stratifying Porous Silicones with Enhanced Liquid Infusion and Protective Skin Layer for Biofouling Prevention %A Vena, Alex %A Kolle, Stefan %A Stafslien, Shane %A Aizenberg, Joanna %A Kim, Philseok %X

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.

%B Advanced Materials Interfaces %V 8 %P 2000359 %G eng %U https://onlinelibrary.wiley.com/doi/full/10.1002/admi.202000359 %N 22 %0 Journal Article %J Energy and Buildings %D 2020 %T Tunable infrared transmission for energy-efficient pneumatic building façades %A Tomholt, Lara %A Geletina, Olga %A Jack Alvarenga %A Shneidman, Anna. V %A Weaver, James C. %A Fernandes, Matheus C. %A Mota, Santiago A. %A Martin Bechthold %A Aizenberg, Joanna %X

Thermal regulation of buildings in climates with daily and seasonal weather changes can prove challenging and result in high building energy consumption. While adaptable façades 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 façades 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’s solar heat gain coefficient (SHGC).

The material’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 façades including real-time operation, ease of implementation and control, and predictable performance. Façade 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.

%B Energy and Buildings %P 110377 %G eng %U https://www.sciencedirect.com/science/article/pii/S0378778819331469?via%3Dihub %N 226 %0 Journal Article %J ACS Nano %D 2020 %T Depletion of Lubricant from Nanostructured Oil-Infused Surfaces by Pendant Condensate Droplets %A Adera, Solomon %A Jack Alvarenga %A Shneidman, Anna. V %A Zhang, Cathy T %A Davitt, Alana %A Aizenberg, Joanna %X

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 “nanostructured lubricated surfaces”) 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–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–Levich–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 °C, and 60% relative humidity, a 2–3-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.

%B ACS Nano %V 14 %P 8024–8035 %G eng %U https://pubs.acs.org/doi/abs/10.1021/acsnano.9b10184 %N 7 %0 Journal Article %J Advanced Functional Materials %D 2020 %T Fabrication of Photonic Microbricks via Crack Engineering of Colloidal Crystals %A Katherine R. Phillips %A Zhang, Cathy T. %A Yang, Ting %A Kay, Theresa %A Gao, Chao %A Brandt, Soeren %A Liu, Lei %A Yang, Haizhao %A Li, Yaning %A Aizenberg, Joanna %A Li, Ling %X

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.

%B Advanced Functional Materials %P 1908242 %G eng %U https://onlinelibrary.wiley.com/doi/full/10.1002/adfm.201908242 %N 30 %0 Journal Article %J Physical Chemistry Chemical Physics %D 2020 %T Neural network assisted analysis of bimetallic nanocatalysts using X-ray absorption near edge structure spectroscopy %A Marcella, N. %A Liu, Yang %A Janis Timoshenko %A Guan, Erija %A Luneau, Mathilde %A Shirman, Tanya %A Plonka, Anna M. %A van der Hoeven, Jessi E. S. %A Aizenberg, Joanna %A Cynthia Friend %A Frenkel, Anatoly I. %X

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–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.


  %B Physical Chemistry Chemical Physics %P 18902-18910 %G eng %U https://pubs.rsc.org/en/content/articlelanding/2020/CP/D0CP02098B %N 22 %0 Journal Article %J Chemistry of MaterialsChemistry of Materials %D 2020 %T Tunable Long-Range Interactions between Self-Trapped Beams driven by the Thermal Response of Photoresponsive Hydrogels %A Meeks, Amos %A Mac, Rebecca %A Chathanat, Simran %A Aizenberg, Joanna %B Chemistry of MaterialsChemistry of Materials %I American Chemical Society %8 2020 %@ 0897-4756 %G eng %U https://doi.org/10.1021/acs.chemmater.0c03702 %! Chem. Mater. %0 Journal Article %J ACS Applied Materials & InterfacesACS Applied Materials & Interfaces %D 2020 %T Dynamic Self-Repairing Hybrid Liquid-in-Solid Protective Barrier for Cementitious Materials %A Paink, Gurminder K. %A Kolle, Stefan %A Le, Duy %A Weaver, James C. %A Jack Alvarenga %A Ahanotu, Onyemaechi %A Aizenberg, Joanna %A Kim, Philseok %X 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’s barrier protection and antifouling properties. Using industry standard test methods for acid resistance, chloride-ion penetrability, freeze–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’s barrier protection and antifouling properties. Using industry standard test methods for acid resistance, chloride-ion penetrability, freeze–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. %B ACS Applied Materials & InterfacesACS Applied Materials & Interfaces %I American Chemical Society %V 12 %P 31922 - 31932 %8 2020 %@ 1944-8244 %G eng %U https://doi.org/10.1021/acsami.0c06357 %N 28 %! ACS Appl. Mater. Interfaces %0 Journal Article %J ACS NanoACS Nano %D 2020 %T Metallic Liquid Gating Membranes %A Alexander B. Tesler %A Zhizhi Sheng %A Lv, Wei %A Fan, Yi %A Fricke, David %A Kyoo-Chul Park %A Jack Alvarenga %A Aizenberg, Joanna %A Xu Hou %B ACS NanoACS Nano %I American Chemical Society %V 14 %P 2465 - 2474 %8 2020 %@ 1936-0851 %G eng %U https://doi.org/10.1021/acsnano.9b10063 %N 2 %! ACS Nano %0 Journal Article %J Proceedings of the National Academy of Sciences %D 2020 %T Opto-chemo-mechanical transduction in photoresponsive gels elicits switchable self-trapped beams with remote interactions %A Morim, Derek R. %A Meeks, Amos %A Shastri, Ankita %A Tran, Andy %A Anna V. Shneidman %A Yashin, Victor V. %A Mahmood, Fariha %A Balazs, Anna C. %A Aizenberg, Joanna %A Saravanamuttu, Kalaichelvi %X 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––over separation distances of up to 10 times the beam width––where such overlap is negligible. %B Proceedings of the National Academy of Sciences %V 117 %P 3953 %8 2020/02/25 %G eng %U http://www.pnas.org/content/117/8/3953.abstract %N 8 %! Proc Natl Acad Sci USA %0 Journal Article %J Soft Matter %D 2020 %T Patterning non-equilibrium morphologies in stimuli-responsive gels through topographical confinement %A Zhang, Cathy T. %A Liu, Ya %A Wang, Xinran %A Wang, Xiaoguang %A Kolle, Stefan %A Balazs, Anna C. %A Aizenberg, Joanna %X Stimuli-responsive “smart” 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. %B Soft Matter %I The Royal Society of Chemistry %V 16 %P 1463 - 1472 %8 2020 %@ 1744-683X %G eng %U http://dx.doi.org/10.1039/C9SM02221J %N 6 %! Soft Matter %0 Journal Article %J Advanced MaterialsAdvanced MaterialsAdv. Mater. %D 2020 %T 3D Printable and Reconfigurable Liquid Crystal Elastomers with Light-Induced Shape Memory via Dynamic Bond Exchange %A Emily C. Davidson %A Arda Kotikian %A Li, Shucong %A Aizenberg, Joanna %A Jennifer A. Lewis %K 3D printing %K dynamic covalent bonds %K light responsive %K liquid crystal elastomers %K shape memory %X 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. %B Advanced MaterialsAdvanced MaterialsAdv. Mater. %I John Wiley & Sons, Ltd %V 32 %P 1905682 %8 2020 %@ 0935-9648 %G eng %U https://doi.org/10.1002/adma.201905682 %N 1 %! Advanced Materials %0 Journal Article %J ChemCatChemChemCatChemChemCatChem %D 2020 %T New Role of Pd Hydride as a Sensor of Surface Pd Distributions in Pd−Au Catalysts %A Guan, Erjia %A Foucher, Alexandre C. %A Marcella, Nicholas %A Shirman, Tanya %A Luneau, Mathilde %A Head, Ashley R. %A Verbart, David M. A. %A Aizenberg, Joanna %A Friend, Cynthia M. %A Stacchiola, Dario %A Stach, Eric A. %A Frenkel, Anatoly I. %K Bimetallic catalysts %K Pd hydride %K Pd−Au nanoparticles %K Surface heterogeneity %K X-ray absorption spectroscopy %X 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. %B ChemCatChemChemCatChemChemCatChem %I John Wiley & Sons, Ltd %V 12 %P 717 - 721 %8 2020 %@ 1867-3880 %G eng %U https://doi.org/10.1002/cctc.201901847 %N 3 %! ChemCatChem %0 Journal Article %J Science Advances %D 2020 %T Twist again: Dynamically and reversibly controllable chirality in liquid crystalline elastomer microposts %A Waters, James T. %A Li, Shucong %A Yuxing Yao %A Lerch, Michael M. %A Aizenberg, Michael %A Aizenberg, Joanna %A Balazs, Anna C. %X 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’s bending respectively changes from light-seeking to light-avoiding. Moreover, both modeling and subsequent experiments show that with the director tilted at 45°, 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 “chimera” posts (encompassing two regions with distinct director orientations) that exhibit simultaneous bending and twisting, mimicking motions exhibited by the human musculoskeletal system. %B Science Advances %V 6 %P eaay5349 %8 2020/03/01 %G eng %U http://advances.sciencemag.org/content/6/13/eaay5349.abstract %N 13 %! Sci Adv %0 Journal Article %J Advanced MaterialsAdvanced MaterialsAdv. Mater. %D 2020 %T Viewpoint: Homeostasis as Inspiration—Toward Interactive Materials %A Lerch, Michael M. %A Alison Grinthal %A Aizenberg, Joanna %K feedback loops %K Homeostasis %K interactivity %K rational design %K self-regulation %X 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. %B Advanced MaterialsAdvanced MaterialsAdv. Mater. %I John Wiley & Sons, Ltd %V 32 %P 1905554 %8 2020 %@ 0935-9648 %G eng %U https://doi.org/10.1002/adma.201905554 %N 20 %! Advanced Materials %0 Journal Article %J ACS Applied Materials & InterfacesACS Applied Materials & Interfaces %D 2020 %T Colorimetric Ethanol Indicator Based on Instantaneous, Localized Wetting of a Photonic Crystal %A Yu, Yanhao %A Brandt, Soeren %A Nicolas, Natalie J. %A Aizenberg, Joanna %B ACS Applied Materials & InterfacesACS Applied Materials & Interfaces %I American Chemical Society %V 12 %P 1924 - 1929 %8 2020 %@ 1944-8244 %G eng %U https://doi.org/10.1021/acsami.9b19836 %N 1 %! ACS Appl. Mater. Interfaces %0 Journal Article %J Journal of Materials Chemistry C %D 2020 %T Silica–titania hybrids for structurally robust inverse opals with controllable refractive index %A Katherine R. Phillips %A Shirman, Tanya %A Aizenberg, Michael %A England, Grant T. %A Vogel, Nicolas %A Aizenberg, Joanna %X 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–gel chemistry, resulting in a mixed oxide with well-dispersed titanium and silicon. Titania has a high refractive index (2.4–2.9), 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. %B Journal of Materials Chemistry C %I The Royal Society of Chemistry %V 8 %P 109 - 116 %8 2020 %@ 2050-7526 %G eng %U http://dx.doi.org/10.1039/C9TC05103A %N 1 %! J. Mater. Chem. C %0 Journal Article %D 2020 %T Non-equilibrium signal integration in hydrogels %A Korevaar, Peter A. %A Kaplan, C. Nadir %A Alison Grinthal %A Rust, Reanne M. %A Aizenberg, Joanna %X 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. %V 11 %P 386 %8 2020 %@ 2041-1723 %G eng %U https://doi.org/10.1038/s41467-019-14114-0 %N 1 %! Nature Communications %0 Journal Article %J Chemical Communications %D 2020 %T Beyond biotemplating: multiscale porous inorganic materials with high catalytic efficiency %A Magnabosco, Giulia %A Papiano, Irene %A Aizenberg, Michael %A Aizenberg, Joanna %A Falini, Giuseppe %X Biotemplating makes it possible to prepare materials with complex structures by taking advantage of nature'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. %B Chemical Communications %I The Royal Society of Chemistry %V 56 %P 3389 - 3392 %8 2020 %@ 1359-7345 %G eng %U http://dx.doi.org/10.1039/D0CC00651C %N 23 %! Chem. Commun. %0 Journal Article %D 2020 %T Enhancing catalytic performance of dilute metal alloy nanomaterials %A Luneau, Mathilde %A Guan, Erjia %A Chen, Wei %A Foucher, Alexandre C. %A Marcella, Nicholas %A Shirman, Tanya %A Verbart, David M. A. %A Aizenberg, Joanna %A Aizenberg, Michael %A Stach, Eric A. %A Madix, Robert J. %A Frenkel, Anatoly I. %A Friend, Cynthia M. %X 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. %V 3 %P 46 %8 2020 %@ 2399-3669 %G eng %U https://doi.org/10.1038/s42004-020-0293-2 %N 1 %! Communications Chemistry %0 Journal Article %J Chemistry of MaterialsChemistry of Materials %D 2019 %T Dilute Pd/Au Alloy Nanoparticles Embedded in Colloid-Templated Porous SiO2: Stable Au-Based Oxidation Catalysts %A Luneau, Mathilde %A Shirman, Tanya %A Filie, Amanda %A Janis Timoshenko %A Chen, Wei %A Trimpalis, Antonios %A Flytzani-Stephanopoulos, Maria %A Kaxiras, Efthimios %A Frenkel, Anatoly I. %A Aizenberg, Joanna %A Friend, Cynthia M. %A Madix, Robert J. %B Chemistry of MaterialsChemistry of Materials %I American Chemical Society %V 31 %P 5759 - 5768 %8 2019 %@ 0897-4756 %G eng %U https://doi.org/10.1021/acs.chemmater.9b01779 %N 15 %! Chem. Mater. %0 Journal Article %J Proceedings of the Royal Society B: Biological SciencesProceedings of the Royal Society B: Biological Sciences %D 2019 %T Structurally assisted super black in colourful peacock spiders %A McCoy, Dakota E. %A McCoy, Victoria E. %A Mandsberg, Nikolaj K. %A Anna V. Shneidman %A Aizenberg, Joanna %A Prum, Richard O. %A Haig, David %B Proceedings of the Royal Society B: Biological SciencesProceedings of the Royal Society B: Biological Sciences %I Royal Society %V 286 %P 20190589 %8 2019 %G eng %U https://doi.org/10.1098/rspb.2019.0589 %N 1902 %! Proceedings of the Royal Society B: Biological Sciences %0 Journal Article %J Crystal Growth & DesignCrystal Growth & Design %D 2019 %T Effect of Surface Chemistry on Incorporation of Nanoparticles within Calcite Single Crystals %A Magnabosco, Giulia %A Polishchuk, Iryna %A Palomba, Francesco %A Rampazzo, Enrico %A Prodi, Luca %A Aizenberg, Joanna %A Pokroy, Boaz %A Falini, Giuseppe %B Crystal Growth & DesignCrystal Growth & Design %I American Chemical Society %V 19 %P 4429 - 4435 %8 2019 %@ 1528-7483 %G eng %U https://doi.org/10.1021/acs.cgd.9b00208 %N 8 %! Crystal Growth & Design %0 Journal Article %J ACS PhotonicsACS Photonics %D 2019 %T Wide-Angle Spectrally Selective Absorbers and Thermal Emitters Based on Inverse Opals %A Shahsafi, Alireza %A Joe, Graham %A Brandt, Soeren %A Anna V. Shneidman %A Stanisic, Nicholas %A Xiao, Yuzhe %A Wambold, Raymond %A Yu, Zhaoning %A Salman, Jad %A Aizenberg, Joanna %A Kats, Mikhail A. %B ACS PhotonicsACS Photonics %I American Chemical Society %V 6 %P 2607 - 2611 %8 2019 %G eng %U https://doi.org/10.1021/acsphotonics.9b00922 %N 11 %! ACS Photonics %0 Journal Article %J Advanced Functional MaterialsAdvanced Functional MaterialsAdv. Funct. Mater. %D 2019 %T Fabrication of Photonic Microbricks via Crack Engineering of Colloidal Crystals %A Katherine R. Phillips %A Zhang, Cathy T. %A Yang, Ting %A Kay, Theresa %A Gao, Chao %A Brandt, Soeren %A Liu, Lei %A Yang, Haizhao %A Li, Yaning %A Aizenberg, Joanna %A Li, Ling %K colloidal crystals %K fracture %K nano/microfabrication %K self-assembly %X 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. %B Advanced Functional MaterialsAdvanced Functional MaterialsAdv. Funct. Mater. %I John Wiley & Sons, Ltd %V n/a %P 1908242 %8 2019 %@ 1616-301X %G eng %U https://doi.org/10.1002/adfm.201908242 %N n/a %! Advanced Functional Materials %0 Journal Article %J Advanced MaterialsAdvanced MaterialsAdv. Mater. %D 2018 %T Designing Liquid-Infused Surfaces for Medical Applications: A Review %A Howell, Caitlin %A Alison Grinthal %A Sunny, Steffi %A Aizenberg, Michael %A Aizenberg, Joanna %K adaptive materials %K antifouling %K devices %K diagnostics %K surface coatings %X 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. %B Advanced MaterialsAdvanced MaterialsAdv. Mater. %I John Wiley & Sons, Ltd %V 30 %P 1802724 %8 2018 %@ 0935-9648 %G eng %U https://doi.org/10.1002/adma.201802724 %N 50 %! Advanced Materials %0 Journal Article %J APL MaterialsAPL Materials %D 2018 %T Research Update: Liquid gated membrane filtration performance with inorganic particle suspensions %A Jack Alvarenga %A Ainge,Yuki %A Williams,Chris %A Maltz,Aubrey %A Blough,Thomas %A Khan,Mughees %A Aizenberg, Joanna %B APL MaterialsAPL Materials %I American Institute of Physics %V 6 %P 100703 %8 2018 %G eng %U https://doi.org/10.1063/1.5047480 %N 10 %! APL Materials %0 Journal Article %J Proceedings of the National Academy of Sciences %D 2018 %T Multiresponsive polymeric microstructures with encoded predetermined and self-regulated deformability %A Yuxing Yao %A Waters, James T. %A Anna V. Shneidman %A Cui, Jiaxi %A Wang, Xiaoguang %A Mandsberg, Nikolaj K. %A Li, Shucong %A Balazs, Anna C. %A Aizenberg, Joanna %X The range of allowed deformation modes currently described for the actuation of microstructures is limited. In this work we introduce magnetic-field–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–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–isotropic transition temperature (TN–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–I, magnetic-field–encoded predetermined deformation at T &gt; TN–I, and direction-dependent self-regulated motion toward the light at T &gt; TN–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. %B Proceedings of the National Academy of Sciences %V 115 %P 12950 %8 2018/12/18 %G eng %U http://www.pnas.org/content/115/51/12950.abstract %N 51 %! Proc Natl Acad Sci USA %0 Journal Article %J Proceedings of the National Academy of Sciences %D 2018 %T Multi-responsive polymeric microstructures with encoded pre-determined and self-regulated deformability %A Yao, Y. %A Waters, J. %A Shneidman, A.V. %A Cui, J. %A X Wang %A Mandsberg, N. K. %A Li, S. %A Balazs, A.C. %A Aizenberg, Joanna %B Proceedings of the National Academy of Sciences %V 115 %P 12950-12955 %G eng %U https://www.pnas.org/content/115/51/12950.abstract %N 51 %0 Journal Article %J Nano Letters %D 2018 %T Probing atomic distributions in mono- and bimetallic nanoparticles by supervised machine learning %A Janis Timoshenko %A Cody Wrasman %A Luneau, Mathilde %A Shirman, Tanya %A Matteo Cargnello %A Simon Bare %A Aizenberg, Joanna %A Cynthia Friend %A Anatoly Frenkel %B Nano Letters %G eng %0 Journal Article %J PHYSICAL REVIEW %D 2018 %T Film Dynamics and Lubricant Depletion by Droplets Moving on Lubricated Surfaces %A Michael J. Kreder %A Dan Daniel %A Adam Tetreault %A Zhenle Cao %A Baptiste Lemaire %A Jaakko V.I. Timonen %A Aizenberg, Joanna %X

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’s speed—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.

%B PHYSICAL REVIEW %V 8 %G eng %N 031053 %0 Journal Article %J Phys. Rev. Lett. %D 2018 %T Origins of liquid-repellency on structured, flat, and lubricated surfaces %A Dan Daniel %A Jaakko V.I. Timonen %A Ruoping Li %A Seneca J. Velling %A Michael J. Kreder %A Adam Tetreault %A Aizenberg, Joanna %X There are currently three main classes of liquid-repellent surfaces: micro-/nano-structured superhydrophobic surfaces, flat surfaces grafted with `liquid-like' 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. %B Phys. Rev. Lett. %G eng %0 Journal Article %J Materials & Design %D 2018 %T Pneumatically adaptive light modulation system (PALMS) for buildings %A K. Hinz %A J. Alvarenga %A Kim, P. %A D. Park %A Aizenberg, J. %A M. Bechthold %X

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 400–900 nm wavelength) to completely diffuse (18.1% T). Changes in the film'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.

%B Materials & Design %V 152 %P 156-167 %G eng %U https://www.sciencedirect.com/science/article/pii/S0264127518303149 %0 Journal Article %J Appl. Phys. Lett. %D 2018 %T Dropwise Condensation on Hydrophobic Bumps and Dimples %A Yuehan Yao %A Aizenberg, Joanna %A Kyoo-Chul Park %X 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. %B Appl. Phys. Lett. %V 112 %P 151605 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:36642002 %N 15 %0 Journal Article %J PNAS %D 2018 %T Directed nucleation and growth by balancing local supersaturation and substrate/nucleus lattice mismatch %A Li, L. %A A. J. Fijneman %A J. A. Kaandorp %A Aizenberg, J. %A W.L. Noorduin %X 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’s remarkable mineralization capabilities and outline fabrication strategies for advanced materials, such as ceramics, photonic structures, and semiconductors. %B PNAS %V 14 %P 3573-3580 %G eng %U http://www.pnas.org/content/early/2018/03/15/1712911115 %0 Journal Article %J Nat. Commun. %D 2018 %T Dynamic air/liquid pockets for guiding microscale flow %A Xu Hou %A Jianyu Li %A Alexander B. Tesler %A Yuxing Yao %A Miao Wang %A Lingli Min %A Zhizhi Sheng %A Aizenberg, Joanna %X

Microscale flows of fluids are mainly guided either by solid matrices or by liquid–liquid interfaces. However, the solid matrices are plagued with persistent fouling problems, while liquid–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–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.

%B Nat. Commun. %V 9 %P 733 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:35015070 %0 Journal Article %J Adv. Mater. %D 2018 %T Nanocrystalline Precursors for the Co-Assembly of Crack-Free Metal Oxide Inverse Opals %A Katherine R. Phillips %A Shirman, Tanya %A Shirman, Elijah %A Anna V. Shneidman %A Theresa M. Kay %A Aizenberg, Joanna %X

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–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.

%B Adv. Mater. %V 30 %P 1706329 %G eng %U https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201706329 %0 Journal Article %J Small %D 2018 %T Bioinspired Universal Flexible Elastomer-Based Microchannels %A Feng Wu %A Songyue Chen %A Baiyi Chen %A Miao Wang %A Lingli Min %A Jack Alvarenga %A Jie Ju %A Ali Khademhosseini %A Yuxing Yao %A Yu Shrike Zhang %A Aizenberg, Joanna %A Xu Hou %X

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.

%B Small %V 14 %P 1702170 %G eng %U https://onlinelibrary.wiley.com/doi/full/10.1002/smll.201702170 %0 Journal Article %J Phys. Rev. Lett. %D 2018 %T Stable Liquid Jets Bouncing off Soft Gels %A Dan Daniel %A Xi Yao %A Aizenberg, Joanna %X

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.

%B Phys. Rev. Lett. %V 120 %P 028006 %G eng %U https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.120.028006 %N 2 %0 Journal Article %J Rep. Prog. Phys. %D 2018 %T Emerging Optical Properties from the Combination of Simple Optical Effects %A England, G.T. %A Aizenberg, J. %X

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—a strategy also found in many natural organisms—to reduce the effects of fabrication imperfections. Furthermore, artificial structures can incorporate materials that are not available to nature—in the form of plasmonic nanoparticles or metal layers—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.

%B Rep. Prog. Phys. %V 81 %P 016402 %G eng %U http://iopscience.iop.org/article/10.1088/1361-6633/aa8372/meta %N 1 %0 Journal Article %J Chem. Eur. J. %D 2018 %T New Architectures for Designed Catalysts: Selective Oxidation using AgAu Nanoparticles on Colloid-Templated Silica %A Shirman, Tanya %A Lattimer, Judith %A Luneau, Mathilde %A Shirman, Elijah %A Reece, Christian %A Aizenberg, Michael %A Madix, Robert J. %A Aizenberg, Joanna %A Friend, Cynthia M. %X

A highly modular synthesis of designed catalysts with controlled bimetallic nanoparticle size and composition and a well-defined structural hierarchy is demonstrated. Exemplary catalysts—bimetallic dilute Ag-in-Au nanoparticles partially embedded in a porous SiO2 matrix (SiO2–AgxAuy)— 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–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.

%B Chem. Eur. J. %V 24 %P 1833 –1837 %G eng %U http://onlinelibrary.wiley.com/doi/10.1002/chem.201704552/full %0 Journal Article %J Adv. Func. Mater. %D 2017 %T Modular Design of Advanced Catalytic Materials Using Hybrid Organic–Inorganic Raspberry Particles %A Shirman, Elijah %A Shirman, Tanya %A Anna V. Shneidman %A Alison Grinthal %A Katherine R. Phillips %A Hayley Whelan %A Eli Bulger %A Marcus Abramovitch %A Jatin Patil %A Rochelle Nevarez %A Aizenberg, Joanna %X

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’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.

%B Adv. Func. Mater. %P 1704559 %G eng %U https://onlinelibrary.wiley.com/doi/full/10.1002/adfm.201704559 %0 Journal Article %J Adv. Func. Mater. %D 2017 %T Inverting the Swelling Trends in Modular Self-Oscillating Gels Crosslinked by Redox-Active Metal Bipyridine Complexes %A Aizenberg, Michael %A Okeyoshi, Kosuke %A Aizenberg, Joanna %X

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–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.

%B Adv. Func. Mater. %P 1704205 %G eng %U http://onlinelibrary.wiley.com/doi/10.1002/adfm.201704205/abstract %0 Journal Article %J Soft Robotics %D 2017 %T A Biologically Inspired, Functionally Graded End Effector for Soft Robotics Applications %A Kumar, Kitty %A Liu, Jia %A Christianson, Caleb %A Ali, Mustafa %A Tolley, Michael T. %A Aizenberg, Joanna %A Ingber, Donald E. %A Weaver, James C. %A Bertoldi, Katia %X

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 ‘‘hybrid appendages’’ 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.

%B Soft Robotics %V 4 %P 317-323 %G eng %U https://www.liebertpub.com/doi/abs/10.1089/soro.2017.0002 %N 4 %0 Journal Article %J Science %D 2017 %T Preventing mussel adhesion using lubricant-infused materials %A Amini, S. %A Kolle, S. %A Petrone, L. %A Ahanotu, O. %A Sunny, S. %A Sutanto, C.N. %A Hoon, S. %A Cohen, L. %A J. C. Weaver %A Aizenberg, J. %A Vogel, N. %A A. Miserez %X

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—from the molecular-scale characterization of deposited adhesive proteins to nanoscale contact mechanics to macroscale live observations—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.

%B Science %V 357 %P 668-673 %G eng %U http://science.sciencemag.org/cgi/content/full/357/6352/668?ijkey=uFJi2l9MM5Mxs&keytype=ref&siteid=sci %N 6352 %0 Journal Article %J Nat. Phys. %D 2017 %T Oleoplaning droplets on lubricated surfaces %A Dan Daniel %A Jaakko V.I. Timonen %A Ruoping Li %A Seneca J. Velling %A Aizenberg, Joanna %X

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◦ . 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–Levich–Derjaguin law. The droplet is therefore oleoplaning—akin to tyres hydroplaning on a wet road—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.

%B Nat. Phys. %V 13 %P 1020-1025 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:34609602 %N 10 %0 Journal Article %J Adv. Mater. %D 2017 %T The Optical Janus Effect: Asymmetric Structural Color Reflection Materials %A England, GT %A Russell, C %A Shirman, E %A Kay, T %A Vogel, N %A Aizenberg, J %X 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. %B Adv. Mater. %V 29 %P 1606876 %G eng %U https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201606876 %N 29 %0 Journal Article %J ACS Nano %D 2017 %T Emerging Trends in Micro- and Nanoscale Technologies in Medicine: From Basic Discoveries to Translation %A Alvarez, MM %A Aizenberg, J %A Analoui, M %A Andrews, AM %A Bisker, G %A Boyden, ES %A Kamm, RD %A Karp, JM %A Mooney, DJ %A Oklu, R %A Peer, D %A Stolzoff, M %A Strano, MS %A Trujillo-de Santiago, G %A Webster, TJ %A Weiss, PS %A Khademhosseini, A %X

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.

%B ACS Nano %V 11 %P 5195-5214 %G eng %U https://pubs.acs.org/doi/abs/10.1021/acsnano.7b01493 %N 6 %0 Journal Article %J Nat. Rev. Mater. %D 2017 %T Interplay between materials and microfluidics %A Hou, X. %A Zhang, Y.S. %A Trujillo-de Santiago, Grissel %A Alvarez, M.M. %A Ribas, J. %A Jonas, S.J. %A Weiss, P.S. %A Andrews, A.M. %A Aizenberg, J. %A Khademhosseini, A. %X

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 — 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.

%B Nat. Rev. Mater. %V 2 %P 17016 %G eng %U https://www.nature.com/articles/natrevmats201716 %N 5 %0 Journal Article %J Science %D 2017 %T Controlled growth and form of precipitating microstructures %A C.N. Kaplan %A W.L. Noorduin %A Li, L. %A R. Sadza %A L. Folkertsma %A Aizenberg, J. %A L. Mahadevan %X

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.

%B Science %V 355 %P 1395-1399 %G eng %U http://science.sciencemag.org/content/355/6332/1395.long %N 6332 %0 Journal Article %J Nat. Commun. %D 2017 %T Photothermally triggered actuation of hybrid materials as a new platform for in vitro cell manipulation %A Sutton, A %A Shirman, T %A Timonen, JVI %A England, GT %A Kim, P %A Kolle, M %A Ferrante, T %A Zarzar, LD %A Strong, E %A Aizenberg, J %X

Mechanical forces in the cell’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.

%B Nat. Commun. %V 8 %P 14700 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:32094141 %0 Journal Article %J Extreme Mechanics Letters %D 2017 %T Harnessing structural instability and material instability in the hydrogel-actuated integrated responsive structures (HAIRS) %A Hu, Y. %A Kim, P. %A Aizenberg, J %X

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.

%B Extreme Mechanics Letters %V 13 %P 84-90 %G eng %0 Journal Article %J Adv. Healthcare Mater. %D 2017 %T Bacterial Interactions with Immobilized Liquid Layer %A Kovalenko, Y %A Sotiri, I %A Timonen, JVI %A Overton, JC %A Homes, G %A Aizenberg, J %A Howell, C %X

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.

%B Adv. Healthcare Mater. %V 6 %P 1600948 %G eng %U https://onlinelibrary.wiley.com/doi/abs/10.1002/adhm.201600948 %N 15 %0 Journal Article %J Biomaterials %D 2017 %T An immobilized liquid interface prevents device associated bacterial infection in vivo %A Chen, J %A Howell, C %A Haller, CA %A Patel, MS %A Ayala, P %A Moravec, KA %A Dai, E %A Liu, L %A Sotiri, I %A Aizenberg, M %A Aizenberg, J %A Chaikof, E %X

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.

%B Biomaterials %V 113 %P 80-92 %8 September 2016 %G eng %0 Journal Article %J Adv. Optical Mater. %D 2016 %T Characterization of a Mechanically Tunable Gyroid Photonic Crystal Inspired by the Butterfly Parides Sesostris %A Pouya, C. %A Overvelde, J.T.B. %A Kolle, M. %A Aizenberg, J. %A Bertoldi, K. %A J. C. Weaver %A P. Vukusic %X A mechanically tunable macroscale replica of the gyroid photonic crystal found in the Parides sesostris butterfly'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. %B Adv. Optical Mater. %V 4 %P 99-105 %G eng %N 1 %0 Journal Article %J Soft Matter %D 2016 %T Computational modeling of oscillating fins that “catch and release“ targeted nanoparticles in bilayer flows %A Liu, Y. %A Bhattacharya, A %A Kuksenok, O %A He, X %A Aizenberg, M %A Aizenberg, J %A Balazs, AC %X

A number of physiological processes in living organisms involve the selective ‘‘catch and release’’ 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, ‘‘catch’’ 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’ oscillation modes on the effective extraction of target species from the upper stream. Our findings provide fundamental insights into the system’s complex dynamics and yield guidelines for fabricating devices for the detection and separation of target molecules from complex fluids.

%B Soft Matter %V 12 %P 1374-1384 %G eng %N 5 %0 Journal Article %J Adv. Mater. %D 2016 %T Extremely Stretchable and Fast Self-Healing Hydrogels %A Jeon, I %A Cui, J %A Illeperuma, WRK %A Aizenberg, J %A Vlassak, JJ %X 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. %B Adv. Mater. %V 28 %P 4678-4683 %G eng %N 23 %0 Journal Article %J ACS Appl. Mater. Interfaces %D 2016 %T Harnessing Cooperative Interactions between Thermoresponsive Aptamers and Gels To Trap and Release Nanoparticles %A Liu, Y. %A Kuksenok, O %A He, X %A Aizenberg, M %A Aizenberg, J %A Balazs, AC %X

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 “catch and release” particles in solution. Our findings provide guidelines for creating fluidic devices that are effective at purifying contaminated solutions or trapping cells for biological assays.

%B ACS Appl. Mater. Interfaces %V 8 %P 30475-30483 %G eng %N 44 %0 Journal Article %J Scientific Reports %D 2016 %T Infused polymers for cell sheet release %A Juthani, N %A Howell, C %A Ledoux, H %A Sotiri, I %A Kelso, S %A Kovalenko, Y %A Tajik, A %A Vu, TL %A Lin, JJ %A Sutton, A %A Aizenberg, J %X

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.

%B Scientific Reports %V 6 %P 26109 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:27662258 %N 1 %0 Journal Article %J ACS Appl. Mater. Interfaces %D 2016 %T Micropatterned Hydrogel Surface with High-Aspect-Ratio Features for Cell Guidance and Tissue Growth %A Hu, Y. %A You, J-O %A Aizenberg, J %X

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.

%B ACS Appl. Mater. Interfaces %V 8 %P 21939-21945 %G eng %N 34 %0 Journal Article %J J. Mater. Chem. A %D 2016 %T Tailoring re-entrant geometry in inverse colloidal monolayers to control surface wettability %A Utech, S %A Bley, K %A Aizenberg, J %A Vogel, N %X

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–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–Baxter wetting states for liquids with low surface tensions, including octane (g ¼ 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.

%B J. Mater. Chem. A %V 4 %P 6853-6859 %G eng %N 18 %0 Journal Article %J Proc. Nat. Acad. Sci. %D 2016 %T Transparent antifouling material for improved operative field visibility in endoscopy %A Sunny, S. %A Cheng, G. %A D. Daniel %A Lo, P. %A Ochoa, S. %A Howell, C. %A Vogel, N. %A Majid, A. %A Aizenberg, J. %X

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 ∼10–15 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 15–20 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 ∼10–15 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.

%B Proc. Nat. Acad. Sci. %V 113 %P 11676-11681 %8 2016 %G eng %N 42 %0 Journal Article %J American Scientist %D 2016 %T A Constructive Chemical Conversation %A Grinthal, A. %A W.L. Noorduin %A Aizenberg, J. %X

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

%B American Scientist %V 104 %P 228-235 %8 Jul-Aug 2016 %G eng %U http://dx.doi.org/10.1511/2016.121.228 %N 4 %0 Journal Article %J ACS Appl. Mater. Interfaces %D 2016 %T Bioinspired Artificial Melanosomes As Colorimetric Indicators of Oxygen Exposure %A C. Shillingford %A Russell, C.W. %A Burgess, I.B. %A Aizenberg, J. %X

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.

%B ACS Appl. Mater. Interfaces %V 8 %P 4314-4317 %8 Feb 18, 2016 %G eng %N 7 %0 Journal Article %J Chem. Soc. Rev. %D 2016 %T A colloidoscope of colloid-based porous materials and their uses %A Phillips, K.R. %A England, G.T. %A Sunny, S. %A Shirman, E. %A Shirman, T. %A Vogel, N. %A Aizenberg, J. %X 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' 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' functions and use, as well as trends in and future directions for the development of CBPM. %B Chem. Soc. Rev. %V 45 %P 281-322 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:31759927 %N 2 %R 10.1039/C5CS00533G %0 Journal Article %J Nature %D 2016 %T Condensation on slippery asymmetric bumps %A K.-C. Park %A Kim, P. %A Grinthal, A. %A N. He %A D. Fox %A J. C. Weaver %A Aizenberg, J. %X 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—based on principles derived from Namib desert beetles, cacti, and pitcher plants—that synergistically combines these aspects of condensation and substantially outperforms other synthetic surfaces. Inspired by an unconventional interpretation of the role of the beetle’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. %B Nature %V 531 %P 78-82 %G eng %N 7592 %R 10.1038/nature16956 %0 Journal Article %J Nat. Rev. Mater. %D 2016 %T Design of anti-icing surfaces: smooth, textured or slippery? %A M.J. Kreder %A J. Alvarenga %A Kim, P. %A Aizenberg, J. %X 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. %B Nat. Rev. Mater. %V 1 %P 15003 %G eng %N 1 %R 10.1038/natrevmats.2015.3 %0 Journal Article %J Scientific Reports %D 2016 %T Tuning and Freezing Disorder in Photonic Crystals using Percolation Lithography %A Burgess, I.B. %A Abedzadeh, N. %A Kay, T.M. %A Shneidman, A.V. %A Cranshaw, D.J. %A Loncar, M. %A Aizenberg, J. %X 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. %B Scientific Reports %V 6 %P 19542 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:24984018 %N 1 %R 10.1038/srep19542 %0 Journal Article %J Soft Matter %D 2015 %T Designing a gel–fiber composite to extract nanoparticles from solution %A Liu, Y. %A Yong, X. %A McFarlin IV, G. %A Kuksenok, O. %A Aizenberg, J. %A Balazs, A.C. %X

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 ‘‘grippers’’ that bind the particles and draw them into the underlying gel. By varying the relative stiffness of the fibers, the fiber–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.

%B Soft Matter %V 11 %P 8692-8700 %G eng %N 44 %0 Journal Article %J Proc. R. Soc. A. %D 2015 %T Elastocapillary coalescence of plates and pillars %A Wei, Z. %A Schneider, T.M. %A Kim, J. %A Kim, H.-J. %A Aizenberg, J. %A L. Mahadevan %X

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.

%B Proc. R. Soc. A. %V 471 %P 20140593 %G eng %N 2175 %0 Journal Article %J Langmuir %D 2015 %T Role of Flagella in Adhesion of Escherichia coli to Abiotic Surfaces %A R.S. Friedlander %A Vogel, N. %A Aizenberg, J. %X

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.

%B Langmuir %V 31 %P 6137-6144 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:33204050 %N 22 %0 Journal Article %J Nat. Chem. %D 2015 %T An aptamer-functionalized chemomechanically modulated biomolecule catch-and-release system %A Shastri, A. %A McGregor, L.M. %A Liu, Y. %A Harris, V. %A Nan, H. %A Mujica, M. %A Vasquez, Y. %A Bhattacharya, A. %A Ma, Y. %A Aizenberg, M. %A Kuksenok, O. %A Balazs, A.C. %A Aizenberg, J. %A He, X. %X 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's stability and amenability to multiple solution recycling. %B Nat. Chem. %V 7 %P 447-454 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:33204049 %N 5 %R 10.1038/NCHEM.2203 %0 Journal Article %J Proc. Nat. Acad. Sci. %D 2015 %T Color from hierarchy: Diverse optical properties of micron-sized spherical colloidal assemblies %A Vogel, N. %A S. Utech %A England, G.T. %A Shirman, T. %A Phillips, K.R. %A N. Koay %A Burgess, I.B. %A Kolle, M. %A D. A. Weitz %A Aizenberg, J. %X 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’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—potentially as more efficient mimics of structural color as it occurs in nature. %B Proc. Nat. Acad. Sci. %V 112 %P 10845-10850 %G eng %U http://www.pnas.org/content/112/35/10845 %N 35 %R 10.1073/pnas.1506272112 %0 Journal Article %J Small %D 2015 %T Combining Bottom-Up Self-Assembly with Top-Down Microfabrication to Create Hierarchical Inverse Opals with High Structural Order %A M. Schaffner %A G. England %A Kolle, M. %A Aizenberg, J. %A Vogel, N. %X 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–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–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. %B Small %V 11 %P 4334-4340 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:27417442 %N 34 %R 10.1002/smll.201500865 %0 Journal Article %J Nat. Mater. %D 2015 %T Dynamic polymer systems with self-regulated secretion for the control of surface properties and material healing %A Cui, J. %A D. Daniel %A Grinthal, A. %A K. Lin %A Aizenberg, J. %X 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’s optical transparency. We foresee diverse applications in fluid delivery, wetting and adhesion control, and material self-repair. %B Nat. Mater. %V 14 %P 790-795 %G eng %U https://www.nature.com/articles/nmat4325 %N 8 %R 10.1038/nmat4325 %0 Journal Article %J Physics of Fluids %D 2015 %T Dynamics of evaporative colloidal patterning %A C.N. Kaplan %A N. Wu %A S. Mandre %A Aizenberg, J. %A L. Mahadevan %X

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.

%B Physics of Fluids %V 27 %P 092105 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:23670482 %N 9 %R 10.1063/1.4930283 %0 Journal Article %J Nat. Commun. %D 2015 %T A highly conspicuous mineralized composite photonic architecture in the translucent shell of the blue-rayed limpet %A Li, L. %A Kolle, S. %A J. C. Weaver %A Ortiz, C. %A Aizenberg, J. %A Kolle, M. %X 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’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’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’ reflection band coincides with the spectral range of minimal light absorption in sea water, raising intriguing questions regarding their functional significance. %B Nat. Commun. %V 6 %P 6322 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:14351052 %R 10.1038/ncomms7322 %0 Journal Article %J Nature %D 2015 %T Liquid-based gating mechanism with tunable multiphase selectivity and antifouling behaviour %A Hou, X. %A Hu, Y. %A Grinthal, A. %A Khan, M. %A Aizenberg, J. %X 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—the pressure needed to open the pores—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–liquid sorting in a microfluidic flow and to separate a three-phase air–water–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. %B Nature %V 519 %P 70-73 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:27657493 %N 7541 %R 10.1038/nature14253 %0 Journal Article %J ACS Biomater. Sci. Eng. %D 2015 %T Liquid-Infused Silicone As a Biofouling-Free Medical Material %A MacCallum, N. %A Howell, C. %A Kim, P. %A Sun, D. %A Friedlander, R. %A Ranisau, J. %A Ahanotu, O. %A Lin, J.J. %A Vena, A. %A Hatton, B. %A T.-S. Wong %A Aizenberg, J. %X 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. %B ACS Biomater. Sci. Eng. %V 1 %P 43-51 %G eng %N 1 %R 10.1021/ab5000578 %0 Journal Article %J Science %D 2015 %T Multifunctionality of chiton biomineralized armor with an integrated visual system %A Li, L. %A Connors, M.J. %A Kolle, M. %A England, G.T. %A Speiser, D.I. %A Xiao, X. %A Aizenberg, J. %A Ortiz, C. %X 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. %B Science %V 350 %P 952-956 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:27663225 %N 6263 %R 10.1126/science.aad1246 %0 Journal Article %J Proc. Nat. Acad. Sci. %D 2015 %T New functional insights into the internal architecture of the laminated anchor spicules of Euplectella aspergillum %A M.A. Monn %A J. C. Weaver %A T. Zhang %A Aizenberg, J. %A H. Kesari %X 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’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. %B Proc. Nat. Acad. Sci. %V 112 %P 4976-4981 %G eng %U http://www.pnas.org/content/112/16/4976 %N 16 %R 10.1073/pnas.1415502112 %0 Journal Article %J Chem. Mater. %D 2015 %T Stability of Surface-Immobilized Lubricant Interfaces under Flow %A Howell, C. %A T.L. Vu %A C.P. Johnson %A Hou, X. %A Ahanotu, O. %A J. Alvarenga %A D.C. Leslie %A O. Uzun %A A. Waterhouse %A Kim, P. %A M. Super %A Aizenberg, M. %A D.E. Ingber %A Aizenberg, J. %X 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. %B Chem. Mater. %V 27 %P 1792-1800 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:27663227 %N 5 %R 10.1021/cm504652g %0 Journal Article %J Nat. Commun. %D 2015 %T Extremely durable biofouling-resistant metallic surfaces based on electrodeposited nanoporous tungstite films on steel %A Tesler, A.B. %A Kim, P. %A Kolle, S. %A Howell, C. %A Ahanotu, O. %A Aizenberg, J. %X 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. %B Nat. Commun. %V 6 %P 8649 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:23993627 %R 10.1038/ncomms9649 %0 Journal Article %J The Journal of Ocean Technology %D 2014 %T Slippery Liquid-Infused Porous Surfaces %A Aizenberg, Joanna %X

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.

%B The Journal of Ocean Technology %V 9 %P 113-114 %8 Winter 2014 %G eng %N 4 %0 Journal Article %J Proc. Nat. Acad. Sci. %D 2014 %T Bioinspired micrograting arrays mimicking the reverse color diffraction elements evolved by the butterfly Pierella luna %A G. England %A Kolle, M. %A Kim, P. %A Khan, M. %A P. Munoz %A E. Mazur %A Aizenberg, J. %X

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.

%B Proc. Nat. Acad. Sci. %V 111 %P 15630–15634 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:27417440 %N 44 %R 10.1073/pnas.1412240111 %0 Journal Article %J Nature Biotechnology %D 2014 %T A bioinspired omniphobic surface coating on medical devices prevents thrombosis and biofouling %A D.C. Leslie %A A. Waterhouse %A J.B. Berthet %A T.M. Valentin %A A.L. Watters %A A. Jain %A Kim, P. %A B.D. Hatton %A A. Nedder %A K. Donovan %A E.H. Super %A Howell, C. %A C.P. Johnson %A T.L. Vu %A D.E. Bolgen %A S. Rifai %A A.R. Hansen %A Aizenberg, M. %A M. Super %A Aizenberg, J. %A D.E. Ingber %X

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.

%B Nature Biotechnology %V 32 %P 1134-1140 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:34298865 %N 11 %R 10.1038/nbt.3020 %0 Journal Article %J Adv. Mater. %D 2014 %T Developmentally-Inspired Shrink-Wrap Polymers for Mechanical Induction of Tissue Differentiation %A B. Hashmi %A L. D. Zarzar %A T. Mammoto %A A. Jiang %A Aizenberg, J. %A D.E. Ingber %X 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. %B Adv. Mater. %V 26 %P 3253-3257 %G eng %U https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201304995 %N 20 %R 10.1002/adma.201304995 %0 Journal Article %J Langmuir %D 2014 %T Directional Wetting in Anisotropic Inverse Opals %A Phillips, K.R. %A Vogel, N. %A Burgess, I.B. %A C.C. Perry %A Aizenberg, J. %X

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.

%B Langmuir %V 30 %P 7615-7620 %G eng %U https://pubs.acs.org/doi/abs/10.1021/la5015253 %N 25 %R 10.1021/la5015253 %0 Journal Article %J Building and Environment %D 2014 %T Dynamic daylight control system implementing thin cast arrays of polydimethylsiloxane-based millimeter-scale transparent louvers %A D. Park %A Kim, P. %A J. Alvarenga %A K. Jin %A Aizenberg, J. %A M. Bechtold %X

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.

%B Building and Environment %V 82 %P 87-96 %G eng %U https://www.sciencedirect.com/science/article/pii/S0360132314002406 %R 10.1016/j.buildenv.2014.07.016 %0 Journal Article %J PLoS ONE %D 2014 %T The Elemental Composition of Demospongiae from the Red Sea, Gulf of Aqaba %A B. Mayzel %A Aizenberg, J. %A M. Ilan %X

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’s coral reefs.

%B PLoS ONE %V 9 %P e95775 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:12152900 %N 4 %R 10.1371/journal.pone.0095775 %0 Journal Article %J Nanotechnology %D 2014 %T Fabrics coated with lubricated nanostructures display robust omniphobicity %A C. Shillingford %A MacCallum, N. %A Wong, T.S. %A Kim, P. %A Aizenberg, J. %X

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.

%B Nanotechnology %V 25 %P 014019 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:27657492 %N 1 %R 10.1088/0957-4484/25/1/014019 %0 Journal Article %J Angew. Chem. Int. Ed %D 2014 %T Fluorogel Elastomers with Tunable Transparency, Elasticity, Shape- Memory, and Antifouling Properties %A X. Yao %A S. Dunn %A Kim, P. %A M. Duffy %A J. Alvarenga %A Aizenberg, J. %X

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.

%B Angew. Chem. Int. Ed %V 53 %P 4418-4422 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:27662698 %N 17 %R 10.1002/anie.201310385 %0 Journal Article %J Opt. Express %D 2014 %T Hierarchical structural control of visual properties in self-assembled photonic-plasmonic pigments %A N. Koay %A I. Burgess %A T. Kay %A B. Nerger %A M. Miles-Rossouw %A Shirman, T. %A T. Vu %A G. England %A K. Phillips %A S. Utech %A Vogel, N. %A Kolle, M. %A and J. Aizenberg %X

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.

%B Opt. Express %V 22 %P 27750-27768 %G eng %U https://doi.org/10.1364/OE.22.027750 %N 23 %R 10.1364/OE.22.027750 %0 Journal Article %J Adv. Funct. Mater. %D 2014 %T Lubricant-infused Nanoparticulate Coatings Assembled by Layer-by-layer Deposition %A Sunny, S. %A Vogel, N. %A Howell, C. %A T.L. Vu %A Aizenberg, J. %X

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.

%B Adv. Funct. Mater. %V 24 %P 6658-6667 %G eng %N 42 %R 10.1002/adfm.201401289 %0 Journal Article %J Chem. Mater. %D 2014 %T Mobile Interfaces: Liquids as a Perfect Structural Material for Multifunctional, Antifouling Surfaces %A Grinthal, A. %A Aizenberg, J. %X

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.

%B Chem. Mater. %V 26 %P 698-708 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:27662700 %N 1 %R 10.1021/cm402364d %0 Journal Article %J Soft Matter %D 2014 %T Photo-tuning of Highly Selective Wetting in Inverse Opals %A T.A. Singleton %A Burgess, I.B. %A B.A. Nerger %A A. Goulet-Hanssens %A N. Koay %A C.J. Barrett %A Aizenberg, J. %X

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.

%B Soft Matter %V 10 %P 1325-1328 %G eng %U http://pubs.rsc.org/en/content/articlelanding/2014/sm/c3sm52684d#!divAbstract %N 9 %R 10.1039/C3SM52684D %0 Journal Article %J Soft Matter %D 2014 %T Reconfigurable soft matter %A Balazs, A.C. %A Aizenberg, J. %B Soft Matter %V 10 %P 1244-1245 %G eng %U http://pubs.rsc.org/en/content/articlelanding/2014/sm/c4sm90006e#!divAbstract %N 9 %R 10.1039/C4SM90006E %0 Journal Article %J ACS Appl. Mater. Interfaces %D 2014 %T Self-Replenishing Vascularized Fouling-Release Surfaces %A Howell, C. %A T.L. Vu %A Lin, J.J. %A Kolle, S. %A N. Juthani %A E. Watson %A J. C. Weaver %A J. Alvarenga %A Aizenberg, J. %X

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.

%B ACS Appl. Mater. Interfaces %V 6 %P 13299-13307 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:27738666 %N 15 %R 10.1021/am503150y %0 Journal Article %J Acc. Chem. Res. %D 2014 %T Stimuli-Responsive Chemomechanical Actuation: A Hybrid Materials Approach %A L. D. Zarzar %A Aizenberg, J. %X

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 “smart” 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 “muscle” that reversibly actuates the microstructured “bones”, 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.

%B Acc. Chem. Res. %V 47 %P 530-539 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:27663228 %N 2 %R 10.1021/ar4001923 %0 Journal Article %J ACS Photonics %D 2014 %T Three-Phase Co-Assembly: In-situ Incorporation of Nanoparticles into Tunable, Highly-Ordered, Porous Silica FIlms %A Vasquez, Y. %A Kolle, M. %A L. Mishchenko %A B.D. Hatton %A Aizenberg, J. %X

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’ 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.

%B ACS Photonics %V 1 %P 53-60 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:33204051 %N 1 %R 10.1021/ph400067z %0 Journal Article %J Chem. Mater. %D 2014 %T Tunable Anisotropy in Inverse Opals and Emerging Optical Properties %A Phillips, K.R. %A Vogel, N. %A Hu, Y. %A Kolle, M. %A C.C. Perry %A Aizenberg, J. %X

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.

%B Chem. Mater. %V 26 %P 1622-1628 %G eng %U https://pubs.acs.org/doi/abs/10.1021/cm403812y %N 4 %R 10.1021/cm403812y %0 Journal Article %J Proc. of SPIE %D 2013 %T Wetting in Color: From photonic fingerprinting of liquids to optical control of liquid percolation %A Burgess, I.B. %A B.A. Nerger %A K.P. Raymond %A A. Goulet-Hanssens %A T.A. Singleton %A M.H. Kinney %A Shneidman, A.V. %A N. Koay %A C.J. Barrett %A Loncar, M. %A Aizenberg, J. %X

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.

%B Proc. of SPIE %V 8632 %P 863201 %G eng %U 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 %0 Journal Article %J MRS Bulletin %D 2013 %T Interfacial materials with special wettability %A T.-S. Wong %A Sun, T. %A Feng, L. %A Aizenberg, J. %X

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.

%B MRS Bulletin %V 38 %P 366-371 %G eng %U https://www.cambridge.org/core/journals/mrs-bulletin/article/interfacial-materials-with-special-wettability/D0E7D6EE5FC8930798D0206C87492E8E %0 Journal Article %J Adv. Funct. Mater. %D 2013 %T New Materials through Bioinspiration and Nanoscience %A Aizenberg, J. %A P. Fratzl %B Adv. Funct. Mater. %V 23 %P 4398-4399 %G eng %U https://doi.org/10.1002/adfm.201302690 %0 Journal Article %J Chem. Soc. Rev. %D 2013 %T Adaptive all the way down: Building responsive materials from hierarchies of chemomechanical feedback %A Grinthal, A. %A Aizenberg, J. %X 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 – as an inherently dynamic, iterative process connecting size and time scales – 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. %B Chem. Soc. Rev. %V 42 %P 7072-7085 %G eng %U http://pubs.rsc.org/en/Content/ArticleLanding/2013/CS/c3cs60045a#!divAbstract %N 17 %R 10.1039/C3CS60045A %0 Journal Article %J Nature Materials %D 2013 %T Adaptive fluid-infused porous films with tunable transparency and wettability %A X. Yao %A Hu, Y. %A Grinthal, A. %A T.-S. Wong %A L. Mahadevan %A Aizenberg, J. %X 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'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. %B Nature Materials %V 12 %P 529-534 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:27417438 %R doi:10.1038/nmat3598 %0 Journal Article %J Solar Energy Materials and Solar Cells %D 2013 %T An artificial vasculature for adaptive thermal control of windows %A B.D. Hatton %A I. Wheeldon %A M.J. Hancock %A Kolle, M. %A Aizenberg, J. %A D.E. Ingber %X 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 10×10 cm2 window by approximately 7–9 °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. %B Solar Energy Materials and Solar Cells %V 117 %P 429-436 %G eng %U https://doi.org/10.1016/j.solmat.2013.06.027 %R 10.1016/j.solmat.2013.06.027 %0 Journal Article %J Proc. Nat. Acad. Sci. %D 2013 %T Bacterial flagella explore microscale hummocks and hollows to increase adhesion %A R.S. Friedlander %A H. Vlamakis %A Kim, P. %A Khan, M. %A Kolter, R. %A Aizenberg, J. %X 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. %B Proc. Nat. Acad. Sci. %V 110 %P 5624-5629 %G eng %U https://doi.org/10.1073/pnas.1219662110 %N 14 %R 10.1073/pnas.1219662110 %0 Journal Article %J New J. Phys %D 2013 %T Biofilm attachment reduction on bioinspired, dynamic, microwrinkling surfaces %A A.K Epstein %A D. Hong %A Kim, P. %A Aizenberg, J. %X 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 (1–100 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. aeruginosaStaphylococcus 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. %B New J. Phys %V 15 %P 095018 %G eng %U http://iopscience.iop.org/article/10.1088/1367-2630/15/9/095018/meta %R 10.1088/1367-2630/15/9/095018 %0 Journal Article %J Adv. Mater. %D 2013 %T Bio-Inspired Band-Gap Tunable Elastic Optical Multilayer Fibers %A Kolle, M. %A A. Lethbridge %A M. Kreysing %A J.J. Baumberg %A Aizenberg, J. %A P. Vukusic %B Adv. Mater. %V 25 %P 2239-2245 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:10235986 %N 15 %R 10.1002/adma.201203529 %0 Journal Article %J Adv. Mater. %D 2013 %T Buckling-Induced Reversible Symmetry Breaking and Amplification of Chirality Using Supported Cellular Structures %A S. H. Kang %A S. Shan %A W.L. Noorduin %A Khan, M. %A Aizenberg, J. %A Bertoldi, K. %B Adv. Mater. %V 25 %P 3380-3385 %G eng %U https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201300617 %N 24 %R 10.1002/adma.201300617 %0 Journal Article %J Chem. Mater. %D 2013 %T Chemo-Mechanically Regulated Oscillation of an Enzymatic Reaction %A He, X. %A R.S. Friedlander %A L. D. Zarzar %A Aizenberg, J. %B Chem. Mater. %V 25 %P 521-523 %G eng %U https://pubs.acs.org/doi/abs/10.1021/cm303313a %N 4 %R 10.1021/cm303313a %0 Journal Article %J Bioinspiration & Biomimetics %D 2013 %T Creating bio-inspired hierarchical 3D–2D photonic stacks via planar lithography on self-assembled inverse opals %A Burgess, I.B. %A Aizenberg, J. %A Loncar, M. %X Structural hierarchy and complex 3D architecture are characteristics of biological photonic designs that are challenging to reproduce in synthetic materials. Top–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–down and bottom–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–down and bottom–up fabrication, may prove useful in the development of omnidirectional coloration elements and 3D–2D photonic crystal devices. %B Bioinspiration & Biomimetics %V 8 %P 045004 %G eng %U http://iopscience.iop.org/article/10.1088/1748-3182/8/4/045004/meta %R 10.1088/1748-3182/8/4/045004 %0 Journal Article %J Appl. Phys. Lett. %D 2013 %T Enhancement of absorption and color contrast in ultra-thin highly absorbing optical coatings %A M. A. Kats %A S. J. Byrnes %A R. Blanchard %A Kolle, M. %A P. Genevet %A Aizenberg, J. %A F. Capasso %X 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. %B Appl. Phys. Lett. %V 103 %P 101104 %G eng %U https://doi.org/10.1063/1.4820147 %R 10.1063/1.4820147 %0 Journal Article %J Nano Lett. %D 2013 %T Hierarchical or Not? Effect of the Length Scale and Hierarchy of the Surface Roughness on Omniphobicity of Lubricant-Infused Substrates %A Kim, P. %A M.J. Kreder %A J. Alvarenga %A Aizenberg, J. %X 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. %B Nano Lett. %V 13 %P 1793-1799 %G eng %U https://pubs.acs.org/doi/abs/10.1021/nl4003969 %N 4 %R 10.1021/nl4003969 %0 Book Section %D 2013 %T Hydrogel-Actuated Integrated Responsive Systems (HAIRS): Creating Cilia-like "Hairy" Surfaces %A Grinthal, A. %A Aizenberg, J. %E J. den Toonder %E P. Onck %I RSC %C Cambridge, U.K. %P 162-185 %G eng %0 Journal Article %J J. Chem. Educ. %D 2013 %T Hydroglyphics: Demonstration of Selective Wetting on Hydrophilic and Hydrophobic Surfaces %A Kim, P. %A J. Alvarenga %A Aizenberg, J. %A R.S. Sleeper %B J. Chem. Educ. %G eng %U https://pubs.acs.org/doi/abs/10.1021/ed3003308 %R 10.1021/ed3003308 %0 Journal Article %J Physical Chemistry Chemical Physics %D 2013 %T Inhibition of Ice Nucleation by Slippery Liquid-Infused Porous Surfaces (SLIPS) %A P.W. Wilson %A W. Lu %A H. Xu %A Kim, P. %A M.J. Kreder %A J. Alvarenga %A Aizenberg, J. %X 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–thaw cycles. %B Physical Chemistry Chemical Physics %V 15 %P 581-585 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:27663226 %R 10.1039/C2CP43586A %0 Journal Article %J Appl. Phys. Lett. %D 2013 %T Lubricant-infused micro/nano-structured surfaces with tunable dynamic omniphobicity at high temperatures %A D. Daniel %A M.N. Mankin %A R.A. Belisle %A T.-S. Wong %A Aizenberg, J. %X Omniphobic surfaces that can repel fluids at temperatures higher than 100 °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 °C. We also demonstrate how liquid mobility on such surfaces can be tuned by a factor of 1000. %B Appl. Phys. Lett. %V 102 %P 231603 %G eng %U http://nrs.harvard.edu/urn-3:HUL.InstRepos:27738667 %R 10.1063/1.4810907 %0 Journal Article %J Adv. Optical Mater. %D 2013 %T Rational Design of Mechano-Responsive Optical Materials by Fine Tuning the Evolution of Strain-Dependent Wrinkling Patterns %A Kim, P. %A Hu, Y. %A J. Alvarenga %A Kolle, M. %A Suo, Z. %A Aizenberg, J. %X 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. %B Adv. Optical Mater. %V 1 %P 381-388 %G eng %U https://doi.org/10.1002/adom.201300034 %N 5 %R 10.1002/adom.201300034 %0 Journal Article %J Science %D 2013 %T Rationally Designed Complex Hierarchical Microarchitectures %A Noorduin, W. %A Grinthal, A. %A L. Mahadevan %A Aizenberg, J. %X 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. %B Science %V 340 %P 832-837 %G eng %U http://science.sciencemag.org/content/340/6134/832 %R 10.1126/science.1234621 %0 Journal Article %J Adv. Funct. Mater. %D 2013 %T Spatial Control of Condensation and Freezing on Superhydrophobic Surfaces with Hydrophilic Patches %A L. Mishchenko %A Aizenberg, J. %A B.D. Hatton %X 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. %B Adv. Funct. Mater. %V 23 %P 4577-4584 %G eng %U https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.201300418 %N 36 %R 10.1002/adfm.201300418 %0 Journal Article %J J. Mater. Chem. C %D 2013 %T Structural Colour in Colourimetric Sensors and Indicators %A Burgess, I.B. %A Loncar, M. %A and J. Aizenberg %X 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. %B J. Mater. Chem. C %V 1 %P 6075-6086 %G eng %U http://pubs.rsc.org/en/content/articlelanding/2013/tc/c3tc30919c#!divAbstract %N 38 %R 10.1039/C3TC30919C %0 Journal Article %J Nature Communications %D 2013 %T Transparency and damage tolerance of patternable omniphobic lubricated surfaces based on inverse colloidal monolayers %A Vogel, N. %A R.A. Belisle %A Hatton, B. %A Wong, T.S. %A Aizenberg, J. %X 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. %B Nature Communications %V 4 %G eng %U https://www.nature.com/articles/ncomms3176 %R 10.1038/ncomms3176 %0 Journal Article %J Lab on a Chip %D 2012 %T Combinatorial Wetting in Colour: An Optofluidic Nose %A K.P. Raymond %A Burgess, I.B. %A M.H. Kinney %A Loncar, M. %A Aizenberg, J. %B Lab on a Chip %V 12 %P 3666-3669 %G eng %R 10.1039/C2LC40489C %0 Journal Article %J Nature Protocols %D 2012 %T Enriching libraries of high-aspect-ratio micro- or nanostructures by rapid, low-cost, benchtop nanofabrication %A Kim, P. %A W.E. Adorno-Martinez %A Khan, M. %A and J. Aizenberg %B Nature Protocols %V 7 %P 311–327 %G eng %N 2 %R 10.1038/nprot.2012.003 %0 Journal Article %J ACS Nano %D 2012 %T Fine-Tuning the Degree of Stem Cell Polarization and Alignment on Ordered Arrays of High-Aspect-Ratio Nanopillars %A M. A. Bucaro %A Vasquez, Y. %A B.D. Hatton %A and J. Aizenberg %B ACS Nano %V 6 %P 6222-6230 %G eng %N 7 %R 10.1021/nn301654e %0 Journal Article %J ACS Nano %D 2012 %T Liquid-Infused Nanostructured Surfaces with Extreme Anti-Ice and Anti-Frost Performance %A Kim, P. %A Wong, T.S. %A J. Alvarenga %A M.J. Kreder %A W.E. Adorno-Martinez %A Aizenberg, J. %B ACS Nano %V 6 %P 6569-6577 %G eng %N 8 %R 10.1021/nn302310q %0 Journal Article %J Proc. Nat. Acad. Sci. USA %D 2012 %T Liquid-infused structured surfaces with exceptional anti-biofouling performance %A A.K Epstein %A Wong, T.S. %A R.A. Belisle %A E.M. Boggs %A Aizenberg, J. %B Proc. Nat. Acad. Sci. USA %V 109 %P 13182-13187 %G eng %N 33 %R 10.1073/pnas.1201973109 %0 Journal Article %J Current Biology %D 2012 %T Mucin Biopolymers Prevent Bacterial Aggregation by Retaining Cells in the Free-Swimming State %A M. Caldara %A R.S. Friedlander %A N.L. Kavanaugh %A Aizenberg, J. %A K.R. Foster %A K. Ribbeck %B Current Biology %V 22 %P 2325-2330 %G eng %N 24 %R 10.1016/j.cub.2012.10.028 %0 Journal Article %J Soft Matter %D 2012 %T Multifunctional Actuation Systems Responding to Chemical Gradients %A L. D. Zarzar %A Liu, Q. %A He, X. %A Hu, Y. %A Suo, Z. %A Aizenberg, J. %B Soft Matter %V 8 %P 8289-8293 %G eng %N 32 %R 10.1039/C2SM26064F %0 Journal Article %J J. Am. Chem. Soc. %D 2012 %T Multiphoton Lithography of Nanocrystalline Platinum and Palladium for Site-Specific Catalysis in 3D Microenvironments %A L. D. Zarzar %A B.S. Swartzentruber %A J.C. Harper %A D.R. Dunphy %A C. J. Brinker %A Aizenberg, J. %A and B. Kaehr %B J. Am. Chem. Soc. %V 134 %P 4007-4010 %G eng %N 9 %R 10.1021/ja211602t %0 Journal Article %J Small %D 2012 %T Patterning Hierarchy in Direct and Inverse Opal Crystals %A L. Mishchenko %A Hatton, B. %A Kolle, M. %A Aizenberg, J. %B Small %V 8 %P 1904-1911 %G eng %N 12 %R 10.1002/smll.201102691 %0 Journal Article %J Small %D 2012 %T Screening Conditions for Rationally Engineered Electrodeposition of Nanostructures (SCREEN): Electrodeposition and Applications of Polypyrrole Nanofibers using MIcrofluidic Gradients %A H. Burgoyne %A Kim, P. %A Kolle, M. %A A.K Epstein %A Aizenberg, J. %B Small %V 8 %P 3502-3509 %G eng %N 22 %R 10.1002/smll.201200888 %0 Journal Article %J Can. J. Chem. %D 2012 %T Secrets revealed - Spatially selective wetting of plasma-patterned periodic mesoporous organosilica %A W. Wang %A Burgess, I.B. %A B.D. Hatton %A J. Alvarenga %A Aizenberg, J. %B Can. J. Chem. %V 90 %P 1063-1068 %G eng %N 12 %R 10.1139/v2012-092 %0 Journal Article %J Nano Today %D 2012 %T Steering nanofibers: An integrative approach to bio-inspired fiber fabrication and assembly %A Grinthal, A. %A S. H. Kang %A A. K. Epstein %A Aizenberg, M. %A Khan, M. %A Aizenberg, J. %B Nano Today %V 7 %P 35-52 %G eng %N 1 %R 10.1016/j.nantod.2011.12.005 %0 Journal Article %J Nano Lett. %D 2012 %T Structural Transformation by Electrodeposition on Patterned Substrates (STEPS) - A New Versatile Nanofabrication Method %A Kim, P. %A A. K. Epstein %A Khan, M. %A L. D. Zarzar %A D. J. Lipomi %A G. M. Whitesides %A and J. Aizenberg %B Nano Lett. %V 12 %P 527-533 %G eng %N 2 %R 10.1021/nl200426g %0 Journal Article %J Nature %D 2012 %T Synthetic Homeostatic Materials with Chemo-Mechano-Chemical Self-Regulation %A He, X. %A Aizenberg, M. %A Kuksenok, O. %A L. D. Zarzar %A Shastri, A. %A Balazs, A.C. %A Aizenberg, J. %B Nature %V 487 %P 214-218 %G eng %R 10.1038/nature11223 %0 Journal Article %J ACS Nano %D 2012 %T Wetting in Color: Colorimetric Differentiation of Organic Liquids with High Selectivity %A Burgess, I.B. %A N. Koay %A K.P. Raymond %A Kolle, M. %A Loncar, M. %A and J. Aizenberg %B ACS Nano %V 6 %P 1427-1437 %G eng %N 12 %R 10.1021/nn204220c %0 Journal Article %J Nano Letters %D 2012 %T Writing on Superhydrophobic Nanopost Arrays: Topographic Design for Bottom-up Assembly %A B.D. Hatton %A Aizenberg, J. %B Nano Letters %V 12 %P 4551-4557 %G eng %N 9 %R 10.1021/nl301775x %0 Journal Article %J Proc. Nat. Acad. Sci. USA %D 2011 %T Bacterial biofilm shows persistent resistance to liquid wetting and gas penetration. %A A. K. Epstein %A B. Pokroy %A A. Seminara %A Aizenberg, J. %B Proc. Nat. Acad. Sci. USA %V 108 %P 995-1000 %G eng %N 3 %R 10.1073/pnas.1011033108 %0 Journal Article %J Adv. Mater. %D 2011 %T Bio-inspired Design of Submerged Hydrogel-Actuated Polymer Microstructures Operating in Response to pH. %A L. D. Zarzar %A Kim, P. %A Aizenberg, J. %B Adv. Mater. %V 23 %P 1442–1446 %G eng %N 12 %R 10.1002/adma.201004231 %0 Journal Article %J Nature %D 2011 %T Bioinspired self-repairing slippery surfaces with pressure-stable omniphobicity %A T.-S. Wong %A S. H. Kang %A S.K.Y. Tang %A E.J. Smythe %A B.D. Hatton %A Grinthal, A. %A and J. Aizenberg %B Nature %V 477 %P 443-447 %G eng %R 10.1038/nature10447 %0 Conference Proceedings %B Proc. SPIE %D 2011 %T Colloidal co-assembly route to large-area high-quality phototonic crystals %A L. Mishchenko %A B.Hatton. I.B. Burgess %A S. David %A K. Sandhage %A Aizenberg, J. %B Proc. SPIE %V 7946 %P 79460K %G eng %R 10.1117/12.881270 %0 Journal Article %J Nature %D 2011 %T Comment in the Nature Special “What lies ahead.” %A Aizenberg, J. %B Nature %V 469 %P 23-25 %G eng %0 Journal Article %J Nanotechnology %D 2011 %T Control of bacterial biofilm growth on surfaces by nanostructural mechanics and geometry %A A. K. Epstein %A A. I. Hochbaum %A Kim, P. %A and J. Aizenberg %B Nanotechnology %V 22 %P 494007 %G eng %N 49 %R doi:10.1088/0957-4484/22/49/494007 %0 Journal Article %J J. Am. Chem. Soc. %D 2011 %T Controlling the Stability and Reversibility of Micropillar Assembly by Surface Chemistry. %A M. Matsunaga %A Aizenberg, M. %A and J. Aizenberg %B J. Am. Chem. Soc. %V 133 %P 5545–5553 %G eng %N 14 %R 10.1021/ja200241j %0 Journal Article %J Angew. Chem. Int. Ed %D 2011 %T Direct Writing and Actuation of Three-Dimensionally Patterned Hydrogel Pads on Micropillar Supports %A L. D. Zarzar %A Kim, P. %A Kolle, M. %A C. J. Brinker %A Aizenberg, J. %A and B. Kaehr %B Angew. Chem. Int. Ed %V 123 %G eng %R 10.1002/ange.201102975 %0 Journal Article %J J. Am. Chem. Soc. %D 2011 %T Encoding complex wettability patterns in chemically functionalized 3D photonic crystals %A Burgess, I.B. %A L. Mishchenko %A B.D. Hatton %A Kolle, M. %A Loncar, M. %A Aizenberg, J. %B J. Am. Chem. Soc. %V 133 %P 12430-12432 %G eng %N 32 %R 10.1021/ja2053013 %0 Conference Proceedings %B Proc. SPIE %D 2011 %T Environmentally responsive active optics based on hydrogel-actuated deformable mirror arrays %A Kim, P. %A L. D. Zarzar %A Khan, M. %A Aizenberg, M. %A Aizenberg, J. %B Proc. SPIE %V 7927 %P 792705 %G eng %R 10.1117/12.879034 %0 Journal Article %J Cryst. Eng. Comm. %D 2011 %T Growth of polygonal rings and wires of CuS on structured surfaces. %A Vasquez, Y. %A E. M. Fenton %A V. F. Chernow %A and J. Aizenberg %B Cryst. Eng. Comm. %V 13 %P 1077-1080 %G eng %R 10.1039/C0CE00499E %0 Journal Article %J Current Opinion in Solid State & Materials Science %D 2011 %T Hydrogel-Actuated Integrated Responsive Systems (HAIRS): Moving towards Adaptive Materials %A Kim, P. %A L. D. Zarzar %A He, X. %A Grinthal, A. %A Aizenberg, J. %B Current Opinion in Solid State & Materials Science %V 15 %P 236-245 %G eng %R 10.1016/j.cossms.2011.05.004 %0 Journal Article %J J. Bacteriology %D 2011 %T Inhibitory Effects of D-Amino Acids on Staphylococcus aureus Biofilm Development %A A. I. Hochbaum %A I. Kolodkin-Gal %A L. Foulston %A Kolter, R. %A Aizenberg, J. %A and R. Losick %B J. Bacteriology %V 193 %P 5616-5622 %G eng %N 20 %R 10.1128/JB.05534-11 %0 Journal Article %J Physical Review B %D 2011 %T Mechanism of nanostructure movement under an electron beam and its application in patterning. %A A. Seminara %A B. Pokroy %A S. H. Kang %A M.P. Brenner %A and J. Aizenberg %B Physical Review B %V 83 %P 235438-1 - 235438-6 %G eng %N 235438 %R 10.1103/PhysRevB.83.235438 %0 Journal Article %J Phys. Rev. Lett. %D 2011 %T Meniscus Lithography: Evaporation-Induced Self-Organization of Pillar Arrays into Moire Patterns %A S. H. Kang %A N. Wu %A Grinthal, A. %A and J. Aizenberg %B Phys. Rev. Lett. %V 107 %P 177802 %G eng %N 17 %R 10.1103/PhysRevLett.107.177802 %0 Journal Article %J Nano Lett. %D 2011 %T Patterning the Tips of Optical Fibers with Metallic Nanostructures Using Nanoskiving. %A D. Lipomi %A Martinez, R. %A M. Kats %A S. H. Kang %A Kim, P. %A Aizenberg, J. %A F. Capasso %A G. Whitesides %B Nano Lett. %V 11 %P 632–636 %G eng %N 2 %R 10.1021/nl103730g %0 Journal Article %J Langmuir %D 2011 %T Predictive Model for Ice Formation on Superhydrophobic Surfaces %A V. Bahadur %A L. Mishchenko %A Hatton, B. %A J. A. Taylor %A Aizenberg, J. %A and T. Krupenkin %B Langmuir %V 27 %P 14143–14150 %G eng %R 10.1021/la200816f %0 Journal Article %J Proc. Nat. Acad. Sci. USA %D 2010 %T Assembly of large-area, highly ordered, crack-free inverse opal films %A Hatton, B. %A L. Mishchenko %A S. Davis %A K. H. Sandhage %A Aizenberg, J. %B Proc. Nat. Acad. Sci. USA %V 107 %P 10354-10359 %G eng %0 Journal Article %J Nano Lett. %D 2010 %T Bacteria Pattern Spontaneously on Periodic Nanostructure Arrays %A A. I. Hochbaum %A Aizenberg, J. %B Nano Lett. %V 10 %P 3717-3721 %G eng %0 Conference Proceedings %B Mater. Res. Soc. Symp. Proc. %D 2010 %T Biomimetic Nanostructured Surfaces with Designer Mechanics and Geometry for Broad Applications %A A. K. Epstein %A and J. Aizenberg %B Mater. Res. Soc. Symp. Proc. %V 1236E %P 1236-SS09-07 %G eng %0 Journal Article %J ACS Nano %D 2010 %T Control of Shape and Size of Nanopillar Assembly by Adhesion-Mediated Elastocapillary Interaction. %A S. H. Kang %A B. Pokroy %A L. Mahadevan %A Aizenberg, J. %B ACS Nano %V 4 %P 6323–6331 %G eng %N 11 %R 10.1021/nn102260t %0 Journal Article %J ACS Nano %D 2010 %T Design of Ice-free Nanostructured Surfaces Based on Repulsion of Impacting Water Droplets. %A L. Mishchenko %A Hatton, B. %A V. Bahadur %A J. A. Taylor %A T. Krupenkin %A Aizenberg, J. %B ACS Nano %V 4 %P 7699–7707 %G eng %N 12 %R 10.1021/nn102557p %0 Journal Article %J ACS Nano %D 2010 %T Fabrication and Replication of Arrays of Single- or Multi-Component Nanostructures by Replica Molding and Mechanical Sectioning %A D. Lipomi %A M. Kats %A Kim, P. %A S. H. Kang %A Aizenberg, J. %A F. Capasso %A G. M. Whitesides %B ACS Nano %V 4 %P 4017-4026 %G eng %0 Journal Article %J Acta Biomater %D 2010 %T A kinetic model of the transformation of a micropatterned amorphous precursor into a porous single crystal %A P. Fratzl %A F. D. Fischer %A J. Svoboda %A Aizenberg, J. %B Acta Biomater %V 6 %P 1001–1005 %G eng %0 Journal Article %J J. Mat. Chem %D 2010 %T Low-Temperature Synthesis of Nanoscale Silica Multilayers – Atomic Layer Deposition in a Test Tube %A Hatton, B. %A V. Kitaev %A D. Perovic %A G. Ozin %A Aizenberg, J. %B J. Mat. Chem %V 20 %P 6009-6013 %G eng %0 Journal Article %J Soft Matter %D 2010 %T Microbristle in gels: Toward all-polymer reconfigurable hybrid surfaces %A Kim, P. %A L. D. Zarzar %A X. Zhao %A A. Sidorenko %A Aizenberg, J. %B Soft Matter %V 6 %P 750-755 %G eng %0 Journal Article %J MRS Bull %D 2010 %T New nanofabrication strategies: Inspired by biomineralization %A Aizenberg, J. %B MRS Bull %V 35 %P 323-330 %G eng %0 Journal Article %J J. Am. Chem. Soc, %D 2010 %T Sonication-assisted synthesis of large, high-quality mercury-thiolate single crystals directly from liquid mercury %A B. Pokroy %A B. Aichmayer %A A. S. Schenk %A B. Haimov %A S. H. Kang %A P. Fratzl %A Aizenberg, J. %B J. Am. Chem. Soc, %V 132 %P 14355–14357 %G eng %N 41 %R 10.1021/ja1056449 %0 Journal Article %J Soft Matter, %D 2010 %T Two-parameter sequential adsorption model applied to microfiber clustering %A J. Paulose %A D. R. Nelson %A Aizenberg, J. %B Soft Matter, %V 6 %P 2421-2434 %G eng %0 Journal Article %J J. Adhesion %D 2010 %T Unifying Design Strategies in Demosponge and Hexactinellid Skeletal Systems %A J. C. Weaver %A G. W. Milliron %A P. Allen %A A. Miserez %A A. Rawal %A J. Garay %A P. J. Thurner %A J. Seto %A B. Mayzel %A L. Jon Friesen %A B. F. Chmelka %A P. Fratzl %A Aizenberg, J. %A Y. Dauphin %A D. Kisailus %A D. E. Morse %B J. Adhesion %V 86 %P 72-95 %G eng %0 Journal Article %J Adv. Mater. %D 2009 %T Biological and Biomimetic Materials %A Aizenberg, J %A P. Fratzl %B Adv. Mater. %V 21 %P 387-388 %G eng %0 Journal Article %J Langmuir %D 2009 %T Crystallization of Malonic and Succinic Acids on SAMs: Toward the General Mechanism of Oriented Nucleation on Organic Monolayers %A B. Pokroy %A V. F. Chernow %A Aizenberg, J. %B Langmuir %V 25 %P 14002-14006 %G eng %0 Journal Article %J Microfluid. Nanofluid. %D 2009 %T Droplet Mixing Using Electrically Tunable Superhydrophobic Nanostructured Surfaces %A E. N. Wang %A M. A. Bucaro %A J. A. Taylor %A P. Kolodner %A Aizenberg, J. %A T. Krupenkin %B Microfluid. Nanofluid. %V 7 %P 137–140 %G eng %0 Conference Proceedings %B Proc. SPIE %D 2009 %T An Evaporative Co-assembly Method for Highly-Ordered Inverse Opal Films %A Hatton, B. %A L. Mishchenko %A R. Norwood %A S. Davis %A K. Sandhage %A Aizenberg, J. %B Proc. SPIE %V 7205 %P 72050-1 %G eng %R 10.1117/12.809656 %0 Journal Article %J Adv. Mater. %D 2009 %T Fabrication of Bio-Inspired Actuated Nanostructures with Arbitrary Geometry and Stiffness %A B. Pokroy %A A. K. Epstein %A M. C. M. Persson-Gulda %A Aizenberg, J. %B Adv. Mater. %V 21 %P 463-469 %G eng %0 Journal Article %J J. Am. Chem. Soc. %D 2009 %T Mechanism of Calcite Co-Orientation in the Sea Urchin Tooth %A C. E. Killian %A R A. Metzler %A Y. Gong %A I. C. Olson %A Aizenberg, J. %A Y. Politi %A F. H. Wilt %A A. Scholl %A A. Young %A A. Doran %A M. Kunz %A N. Tamura %A S. N. Coppersmith %A P.U.P.A. Gilbert %B J. Am. Chem. Soc. %V 131 %P 18404–18409 %G eng %0 Journal Article %J Science %D 2009 %T Self-Organization of a Mesoscale Bristle into Ordered, Hierarchical Helical Assemblies %A B. Pokroy %A S. H. Kang %A L. Mahadevan %A Aizenberg, J. %B Science %V 323 %P 237-240 %G eng %0 Journal Article %J Langmuir %D 2009 %T Tunable Liquid Optics: Electrowetting-Controlled Liquid Mirrors Based on Self-Assembled Janus Tiles %A M. Bucaro %A P. Kolodner %A J. A. Taylor %A A. Sidorenko %A Aizenberg, J. %A T. Krupenkin %B Langmuir %V 25 %P 3876-3879 %G eng %0 Journal Article %J Chem. Mater. %D 2008 %T Calcium Carbonate Storage in Amorphous Form and Its Template-Induced Crystallization %A T. Y.-J. Han %A Aizenberg, J. %B Chem. Mater. %V 20 %P 1064-1068 %G eng %0 Journal Article %J invited paper, J. Mater. Chem. %D 2008 %T Controlled Switching of the Wetting Behavior of Biomimetic Surfaces with Hydrogel-Supported Nanostructures %A A. Sidorenko %A T. Krupenkin %A Aizenberg, J. %B invited paper, J. Mater. Chem. %V 18 %P 3841-3846 %G eng %0 Journal Article %J Adv. Funct. Mater. %D 2008 %T Effects of Laminate Architecture on Fracture Resistance of Sponge Biosilica: Lessons from Nature %A A. Miserez %A J. C. Weaver %A P. J. Thurner %A Aizenberg, J. %A Y. Dauphin %A P. Fratzl %A D. E. Morse %A F. W. Zok %B Adv. Funct. Mater. %V 18 %P 1-8 %G eng %0 Book Section %D 2008 %T Self-Assembled Monolayers as Templates for Inorganic Crystallization: A Bio-Inspired Approach %A Aizenberg, J. %E J.J. Novoa %I Dordrecht, Netherlands %C Springer WB/Nato Publishing Unit %P 17 - 32 %G eng %0 Journal Article %J CrystEngComm %D 2007 %T Calcite Shape Modulation through the Lattice Mismatch between the Self-Assembled Monolayer Template and the Nucleated Crystal Face %A B. Pokroy %A Aizenberg, J. %B CrystEngComm %V 9 %P 1219-1225 %G eng %0 Journal Article %J J. Struct. Biol. %D 2007 %T Hierarchical Assembly of the Siliceous Skeletal Lattice of the Hexactinellid Sponge Euplectella aspergillum %A J. C. Weaver %A Aizenberg, J. %A G. E. Fantner %A D. Kisailus %A A. Woesz %A P. Allen %A K. Fields %A M. J. Porter %A F. W. Zok %A P. K. Hansma %A P. Fratzl %A D. E. Morse %B J. Struct. Biol. %V 158 %P 93–106 %G eng %0 Journal Article %J Science %D 2007 %T Reversible Switching of Hydrogel-Actuated Nanostructures into Complex Micropatterns %A A. Sidorenko %A T. Krupenkin %A A. Taylor %A P. Fratzl %A Aizenberg, J. %B Science %V 315 %P 487-490 %G eng %0 Conference Proceedings %B Mater. Res. Soc. Symp. Proc. %D 2006 %T Accelerated Chemical Reactions for Lab-on-a-Chip Applications Using Electrowetting-Induced Droplet Self-Oscillations %A Aizenberg, J. %A T. Krupenkin %A P. Kolodner %B Mater. Res. Soc. Symp. Proc. %V 915 %P 0915-R06-10 %G eng %0 Journal Article %J J. Mater. Res. %D 2006 %T Micromechanical Properties of Biological Silica in Skeletons of Deep-Sea Sponges %A A. Woesz %A J. C. Weaver %A M. Kazanci %A Y. Dauphin %A D. E. Morse %A Aizenberg, J. %A P. Fratzl %B J. Mater. Res. %V 21 %P 2068-2078 %G eng %0 Conference Proceedings %B Proc. Am. Chem. Soc. PMSE %D 2006 %T Selective Trapping of Nanoparticles on Adaptive, Topographic Surfaces %A Zhang, Y. %A S. Qin %A J. A. Taylor %A Aizenberg, J. %A Yang, S. %B Proc. Am. Chem. Soc. PMSE %V 94 %P 852 %G eng %0 Journal Article %J J. Micromech. Microeng %D 2006 %T Tunable Microfluidic Optical Devices with an Integrated Microlens Array %A K.-S. Hong %A J. Wang %A A. Sharonov %A D. Chandra %A Aizenberg, J. %A Yang, S. %B J. Micromech. Microeng %V 16 %P 1660-1666 %G eng %0 Journal Article %J Bell Labs Technical Journal %D 2005 %T Bio-Inspired Approach to Controlled Crystallization at the Nanoscale %A Aizenberg, J. %B Bell Labs Technical Journal %V 10 %P 129-141 %G eng %N 3 %0 Conference Proceedings %B Proc. Am. Chem. Soc. PMSE %D 2005 %T Controlled Synthesis of Micropatterned Single Crystals via Amorphous-to-Crystalline Transition Induced by Polymer-Modified 3D Templates %A Aizenberg, J. %B Proc. Am. Chem. Soc. PMSE %V 325 %G eng %0 Conference Proceedings %B Proc. 8th International Conference on the Chemistry and Biology of Mineralized Tissues %D 2005 %T Effects of Magnesium Ions on Crystallization and Morphogenesis of Oriented Calcite Crystals Templated by Organic Surfaces %A Y.-J. Han %A Aizenberg, J. %B Proc. 8th International Conference on the Chemistry and Biology of Mineralized Tissues %P 212-215 %G eng %0 Journal Article %J Adv. Mater. %D 2005 %T Functional Biomimetic Microlens Arrays With Integrated Pores %A Yang, S. %A G. Chen %A Megens, M. %A C. K. Ullal %A Y.-J. Han %A R. Rapaport %A E. L. Thomas %A Aizenberg, J. %B Adv. Mater. %V 17 %P 435-438 %G eng %0 Journal Article %J Appl. Phys. Lett %D 2005 %T Microlens Arrays with Integrated Pores as a Multipattern Photomask %A Yang, S. %A C. K. Ullal %A E. L. Thomas %A G. Chen %A Aizenberg, J. %B Appl. Phys. Lett %V 86 %P 201121 %G eng %0 Conference Proceedings %B Proc. Digital Fabrication (IS&T) %D 2005 %T Multifunctional Biomimetic Microlens Arrays with Integrated Pores %A Yang, S. %A Aizenberg, J. %B Proc. Digital Fabrication (IS&T) %P 164 %G eng %0 Journal Article %J Nano Today %D 2005 %T Multifunctional Biomimetic Microlens Arrays with Integrated Pores %A Yang, S. %A Aizenberg, J. %B Nano Today %V 12 %P 40-46 %G eng %0 Book Section %D 2005 %T Nanomechanics of Biological Single Crystals: The Role of Intracrystalline Proteins %A Aizenberg, J. %E T.-J. Chuang %E P. M. Anderson %E M.-K. Wu and S. Hsieh %I Springer %C Dordrecht, Netherlands %P 99-108 %G eng %0 Book Section %D 2005 %T Optical Fibers of Deep Sea Sponges %A A. Yablon %A Aizenberg, J. %I McGraw-Hill %G eng %0 Journal Article %J Cryst. Growth Des. %D 2005 %T Orientation and Mg Incorporation of Calcite Grown on Functionalized Self-Assembled Monolayers: A Synchrotron X-ray Study %A S.-Y. Kwak %A E. DiMasi %A Y.-J. Han %A Aizenberg, J. %B Cryst. Growth Des. %V 5 %P 2139-2145 %G eng %0 Journal Article %J J. Am. Chem. Soc %D 2005 %T Patterned Growth of Large Oriented Organic Semiconductor Single Crystals on Self-Assembled Monolayer Templates %A A. L. Briseno %A Y.-J. Han %A R. A. Penkala %A H. Moon %A A. J. Lovinger %A C. Kloc %A Z. Bao %A Aizenberg, J. %B J. Am. Chem. Soc %V 127 %P 12164-12165 %G eng %0 Journal Article %J Science %D 2005 %T Skeleton of Euplectella sp.: Structural Hierarchy from the Nanoscale to the Macroscale %A Aizenberg, J. %A J. C. Weaver %A M. S. Thanawala %A V. C. Sundar %A D. E. Morse %A P. Fratzl %B Science %V 309 %P 275-278 %G eng %0 Conference Proceedings %B Mater. Res. Soc. Symp. Proc. %D 2005 %T Surface-Induced Recrystallization of Amorphous Calcium Carbonates to Oriented Calcite Crystals %A Y.-J. Han %A Aizenberg, J. %B Mater. Res. Soc. Symp. Proc. %V 873E %P K4.10 %G eng %0 Journal Article %J J. Mater. %D 2005 %T Synthesis of Photoacid Crosslinkable Hydrogels for the Fabrication of Soft, Biomimetic Microlens Arrays %A Yang, S. %A J. Ford %A C. Ruengruglikit %A Q. Huang %A Aizenberg, J. %B J. Mater. %V 15 %P 4200-4202 %G eng %0 Conference Proceedings %B Proc. Am. Chem. Soc. PMSE %D 2005 %T Synthetic Biomimetic Microlens Arrays from Polymers %A Aizenberg, J. %A Yang, S. %B Proc. Am. Chem. Soc. PMSE %V 93 %P 133 %G eng %0 Journal Article %J Angew. Chem. Int. Ed %D 2005 %T Template-Dependent Morphogenesis of Oriented Calcite Crystals in the Presence of Magnesium Ions %A Y.-J. Han %A L. M. Wysocky %A M. Thanawala %A T. Siegrist %A Aizenberg, J. %B Angew. Chem. Int. Ed %V 44 %P 2386 - 2390 %G eng %0 Conference Proceedings %B Proc. Am. Chem. Soc. PMSE %D 2004 %T Bio-Inspired Periodic Microlens Arrays with Integrated Pore Structures Created by Multiple-Beam Interference Lithography %A Yang, S. %A G. Chen %A Megens, M. %A C. K. Ullal %A Y.-J. Han %A R. Rapaport %A C. Ruengruglikit %A Q. Huang %A E. L. Thomas %A Aizenberg, J. %B Proc. Am. Chem. Soc. PMSE %V 90 %P 379 %G eng %0 Journal Article %J Proc. Nat. Acad. Sci. USA %D 2004 %T Biological Glass Fibers:  Correlation between Optical and Structural Properties %A Aizenberg, J. %A V. C. Sundar %A A. D. Yablon %A J. C. Weaver %A G. Chen %B Proc. Nat. Acad. Sci. USA %V 101 %P 3358-3363 %G eng %0 Journal Article %J Adv. Mater. %D 2004 %T Crystallization in Patterns:  A Bio-Inspired Approach %A Aizenberg, J. %B Adv. Mater. %V 16 %P 1295-1302 %G eng %0 Journal Article %J J. Mater. Chem. %D 2004 %T Designing Efficient Microlens Arrays:  Lessons from Nature %A Aizenberg, J. %A Hendler, G. %B J. Mater. Chem. %V 14 %P 2066-2072 %G eng %0 Book Section %D 2004 %T Learning From Marine Creatures %A Aizenberg, J. %A Hendler, G. %E R. L. Reis and S. Weiner %I Kluwer Acad. Publ. %C Netherlands %P 151-166 %G eng %0 Book Section %D 2004 %T Multilevel Control of Calcite Crystallization Using Self-Assembled Monolayers %A Aizenberg, J. %E I. Kobayashi %E H. Ozawa %I Tokai Univ. Press %C Japan %P 209-214 %G eng %0 Journal Article %J J. Mater. Chem. %D 2004 %T New Developments in Bio-Related Materials %A Aizenberg, J. %A J. Livage %A S. Mann %B J. Mater. Chem. %V 14 %P E5-E6 %G eng %0 Conference Proceedings %B Mater. Res. Soc. Proc. %D 2004 %T Photonic Crystals Through Interference Lithography: A Level Set Approach %A C. Ullal %A M. Maldovan %A Yang, S. %A G. Chen %A Y-J. Han %A Aizenberg, J. %A R. Rapaport %A C. White %A E. L. Thomas %B Mater. Res. Soc. Proc. %V EXS-2 %P 179-181 %G eng %0 Conference Proceedings %B Mater. Res. Soc. Proc. %D 2004 %T Shape, Size and Morphology Control of Inorganic Crystals With Self-Assembled Monolayers %A Y.-J. Han %A Aizenberg, J. %B Mater. Res. Soc. Proc. %V 823 %P 115-119 %G eng %0 Journal Article %J Connect. Tissue Res. %D 2003 %T Coexistence of Amorphous and Crystalline Calcium Carbonate in Skeletal Tissues %A Aizenberg, J. %A S. Weiner %A L. Addadi %B Connect. Tissue Res. %V 44 %P 20-25 %G eng %0 Journal Article %J Science %D 2003 %T Direct Fabrication of Large Micropatterned Single Crystals %A Aizenberg, J. %A D. A. Muller %A J. L. Grazul %A D. R. Hamann %B Science %V 299 %P 1205-1208 %G eng %0 Journal Article %J J. Am. Chem. Soc. %D 2003 %T Effect of Magnesium Ions on Oriented Growth of Calcite on Carboxylic Acid Functionalized Self-Assembled Monolayer %A Y.-J. Han %A Aizenberg, J. %B J. Am. Chem. Soc. %V 125 %P 4032-4033 %G eng %0 Journal Article %J Angew. Chem. Int. Ed. %D 2003 %T Face-Selective Nucleation of Calcite on Self-Assembled Monolayers of Alkanethiols: Effect of the Parity of the Alkyl Chain %A Y.-J. Han %A Aizenberg, J. %B Angew. Chem. Int. Ed. %V 42 %P 3668-3670 %G eng %0 Journal Article %J Nature %D 2003 %T Fiber-Optical Features of a Glass Sponge %A V. C. Sundar %A A. D. Yablon %A J. L. Grazul %A M. Ilan %A Aizenberg, J. %B Nature %V 424 %P 899-900 %G eng %0 Journal Article %J Nature %D 2003 %T Like-Charged Particles at Liquid Interfaces %A Megens, M. %A Aizenberg, J. %B Nature %V 424 %P 1014 %G eng %0 Journal Article %J Appl. Phys. Lett. %D 2003 %T Narrow Features in Metals at the Interfaces Between Different Etch Resists %A V. C. Sundar %A Aizenberg, J. %B Appl. Phys. Lett. %V 83 %P 2259-2261 %G eng %0 Conference Proceedings %B Mater. Res. Soc. Proc. %D 2003 %T Structural and Initial Optical Characterization of Basalia Spicules in the Glass Sponge Euplectella %A V. C. Sundar %A J. Grazul %A Aizenberg, J. %B Mater. Res. Soc. Proc. %V 774 %P 115-119 %G eng %0 Conference Proceedings %B Proc. Am. Chem. Soc. PMSE %D 2002 %T Creating Periodic 3D Structures by Multiple-Beam Interference of Visible Laser %A Yang, S. %A Megens, M. %A Wiltzius, P. %A Aizenberg, J. %B Proc. Am. Chem. Soc. PMSE %V 43 %P 548 %G eng %N 2 %0 Journal Article %J Chem. Mater %D 2002 %T Creating Periodic Three-Dimensional Structures by Multibeam Interference of Visible Laser %A Yang, S. %A Megens, M. %A Aizenberg, J. %A Wiltzius, P. %A P. M. Chaikin %A W. B. Russel %B Chem. Mater %V 14 %P 2831-2833 %G eng %0 Journal Article %J J. Am. Chem. Soc. %D 2002 %T Factors Involved in the Formation of Amorphous and Crystalline Calcium Carbonate:  A Study of an Ascidian Skeleton %A Aizenberg, J. %A G. Lambert %A S. Weiner %A L. Addadi %B J. Am. Chem. Soc. %V 124 %P 32-39 %G eng %0 Journal Article %J Nature %D 2001 %T Calcitic Microlenses as Part of the Photoreceptor System in Brittlestars %A Aizenberg, J. %A Tkachenko, A. %A S. Weiner %A L. Addadi %A Hendler, G. %B Nature %V 412 %P 819-822 %G eng %0 Conference Proceedings %B Mater. Res. Soc. Proc. %D 2001 %T Templated crystallization of calcite on patterned self-assembled monolayers %A Aizenberg, J. %B Mater. Res. Soc. Proc. %V 620 %P M4.1.1-10 %G eng %0 Journal Article %J Phys. Rev. Lett. %D 2000 %T Patterned Colloidal Deposition Controlled by Electrostatic and Capillary Forces %A Aizenberg, J. %A P. V. Braun %A Wiltzius, P. %B Phys. Rev. Lett. %V 84 %P 2997-3000 %G eng %0 Journal Article %J J. Chem. Soc. Dalton Trans. %D 2000 %T Patterned Crystallisation on Self-Assembled Monolayers with Integrated Regions of Disorder %A Aizenberg, J. %B J. Chem. Soc. Dalton Trans. %P 3963-3968 %G eng %0 Journal Article %J J. Crystal Growth %D 2000 %T Patterned Crystallization of Calcite in Vivo and in Vitro %A Aizenberg, J. %B J. Crystal Growth %V 211 %P 143-148 %G eng %0 Journal Article %J Appl. Phys. Lett. %D 2000 %T Ultraviolet Lithography of Self-Assembled Monolayers for Submicron Patterned Deposition %A S. Friebel %A Aizenberg, J. %A S. Abad %A Wiltzius, P. %B Appl. Phys. Lett. %V 77 %P 2406-2408 %G eng %0 Book Section %D 1999 %T On the concept of a single crystal in biomineralization %A L. Addadi %A Aizenberg, J. %A E. Beniash %A S. Weiner %I Kluwer Acad. Publ. %C Dordrecht, Netherlands %G eng %0 Journal Article %J Nature %D 1999 %T Control of Nucleation by Patterned Self-Assembled Monolayers %A Aizenberg, J. %A A. J. Black %A G. M. Whitesides %B Nature %V 398 %P 495-498 %G eng %0 Conference Proceedings %B Proc. Am. Chem. Soc., PMSE %D 1999 %T Engineering the Microenvironment of Crystals Nucleation and Growth Using Micropatterned Polymers %A Aizenberg, J. %A A. J. Black %A G. M. Whitesides %B Proc. Am. Chem. Soc., PMSE %V 81 %P 2-3 %G eng %0 Journal Article %J J. Am. Chem. Soc. %D 1999 %T Oriented Growth of Calcite Controlled by Self-Assembled Monolayers of Functionalized Alkanethiols Supported on Gold and Silver %A Aizenberg, J. %A A. J. Black %A G. M. Whitesides %B J. Am. Chem. Soc. %V 121 %P 4500-4509 %G eng %0 Journal Article %J J. Am. Chem. Soc. %D 1999 %T Patterning Disorder in Monolayer Resists for the Fabrication of sub-100-nm Structures in Silver, Gold, Silicon, and Aluminum %A A. J. Black %A K. E. Paul %A Aizenberg, J. %A G. M. Whitesides %B J. Am. Chem. Soc. %V 121 %P 8356-8365 %G eng %0 Journal Article %J Nature %D 1998 %T Controlling Local Disorder in Self-Assembled Monolayers by Patterning the Topography of their Metallic Supports %A Aizenberg, J. %A A. J. Black %A G. M. Whitesides %B Nature %V 394 %P 868-871 %G eng %0 Journal Article %J Appl. Opt. %D 1998 %T Imaging Profiles of Light Intensity in the near field: Applications to Phase-Shift Photolithography %A Aizenberg, J. %A J. A. Rogers %A K. E. Paul %A G. M. Whitesides %B Appl. Opt. %V 37 %P 2145-2152 %G eng %0 Journal Article %J Appl. Phys. Lett. %D 1998 %T Maskless Photolithography:  Embossed Photoresist as Its Own Optical Element %A K. E. Paul %A T. L. Breen %A Aizenberg, J. %A G. M. Whitesides %B Appl. Phys. Lett. %V 73 %P 2893-2895 %G eng %0 Journal Article %J Proc. R. Soc. Lond. B. %D 1997 %T Amorphous Calcium Carbonate Transforms into Calcite during Sea Urchin Larval Spicule Growth %A E. Beniash %A Aizenberg, J. %A L. Addadi %A S. Weiner %B Proc. R. Soc. Lond. B. %V 264 %P 461-465 %G eng %0 Journal Article %J J. Am. Chem. Soc. %D 1997 %T Control of Macromolecule Distribution within Synthetic and Biogenic Single Calcite Crystals %A Aizenberg, J. %A J. Hanson %A T. F. Koetzle %A S. Weiner %A L. Addadi %B J. Am. Chem. Soc. %V 119 %P 881-886 %G eng %0 Journal Article %J Appl. Phys. Let. %D 1997 %T Imaging the Irradiance Distribution in the Optical Near Field %A Aizenberg, J. %A J. A. Rogers %A K. E. Paul %A G. M. Whitesides %B Appl. Phys. Let. %V 71 %P 3773-3775 %G eng %0 Journal Article %J Proc. R. Soc. Lond. B. %D 1996 %T Dynamics and Growth Patterns of Calcareous Sponge Spicules %A M. Ilan %A Aizenberg, J. %A O. Gilor %B Proc. R. Soc. Lond. B. %V 263 %P 133-139 %G eng %0 Journal Article %J Connect. Tissue Res. %D 1996 %T Intracrystalline Macromolecules are Involved in the Morphogenesis of Calcitic Sponge Spicules %A Aizenberg, J. %A M. Ilan %A S. Weiner %A L. Addadi %B Connect. Tissue Res. %V 34 %P 255-261 %G eng %0 Journal Article %J Adv. Mat. %D 1996 %T Stabilization of Amorphous Calcium Carbonate by Specialized Macromolecules in Biological and Synthetic Precipitates %A Aizenberg, J. %A G. Lambert %A L. Addadi %A S. Weiner %B Adv. Mat. %V 8 %P 222-225 %G eng %0 Journal Article %J Chem. Eur. J. %D 1995 %T Biologically-Induced Reduction in Symmetry:  A Study of Crystal Texture of Calcitic Sponge Spicules %A Aizenberg, J. %A J. Hanson %A T. F. Koetzle %A L. Leiserowitz %A S. Weiner %A L. Addadi %B Chem. Eur. J. %V 7 %P 414-422 %G eng %0 Journal Article %J FASEB J. %D 1995 %T Morphogenesis of Calcitic Sponge Spicules:  A Role for Specialized Proteins Interacting with Growing Crystals %A Aizenberg, J. %A J. Hanson %A M. Ilan %A L. Leiserowitz %A T. F. Koetzle %A L. Addadi %A S. Weiner %B FASEB J. %V 9 %P 262-268 %G eng %0 Book Section %D 1995 %T Structural control over the formation of calcium carbonate mineral phases in biomineralization %A L. Addadi %A Aizenberg, J. %A S. Albeck %A G. Falini %A S. Weiner %E J. S. Siegel %I Kluwer Acad. Publ. %C Netherlands %P 127-139 %G eng %0 Journal Article %J Mol. Cryst. Liquid Cryst. Sci. Technol. %D 1994 %T Controlled Occlusion of Proteins: A Tool for Modulating the Properties of Skeletal Elements %A L. Addadi %A Aizenberg, J. %A S. Albeck %A A. Berman %A L. Leiserowitz %A S. Weiner %B Mol. Cryst. Liquid Cryst. Sci. Technol. %V 248 %P 185-198 %G eng %0 Journal Article %J J. Cryst. Growth %D 1994 %T Crystal - Protein Interactions Studied by Overgrowth of Calcite on Biogenic Skeletal Elements %A Aizenberg, J. %A S. Albeck %A S. Weiner %A L. Addadi %B J. Cryst. Growth %V 142 %P 156-164 %G eng %0 Journal Article %J J. Am. Chem. Soc. %D 1993 %T Interactions of Various Skeletal Intracrystalline Components with Calcite Crystals %A S. Albeck %A Aizenberg, J. %A L. Addadi %A S. Weiner %B J. Am. Chem. Soc. %V 115 %P 11691-11697 %G eng %0 Journal Article %J Vestnik  Mosk. Univ. %D 1984 %T Calculation of the Rate Constants of Monomolecular Chemical Reactions in the Gas Phase by Semiempirical Method Based on the Slater Theory %A M. T. Bairamov %A Aizenberg, J. %A A. K. Keroglu %B Vestnik  Mosk. Univ. %V 3 %P 55-59 %G eng