# Hydrogel-Actuated Materials ## expand\_more #### Hydrogel-Actuated Responsive Structures Dynamic structures that respond reversibly to changes in their environment are central to self-regulating thermal and lighting systems, targeted drug delivery, sensors, and self-propelled locomotion. Since an adaptive change requires energy input, an ideal strategy would be to design materials that harvest energy directly from the changing condition itself and use it to drive an appropriate response. Based on this concept, we have developed a class of adaptive materials known as HAIRS (Hydrogel-Actuated Integrated Responsive Structures), that, similar to skeletomuscular systems, use a hybrid architecture to interconvert energy between different forms and scales. HAIRS consist of flexible, high-aspect-ratio polymer or silicon structures coupled with a responsive hydrogel, where the hydrogel, upon expansion and contraction, acts as a "muscle" to move or actuate the passive polymer "bones". To specify the materials’ functions, we use surfaces bearing arrays of nanostructures. We have investigated humidity, pH, and temperature responsive surfaces, and aim to expand to light and redox sensitive surfaces. We are able to control actuation direction by a variety of methods, including topographical patterning of the hydrogel, "shadow curing" of the hydrogel, the use of anisotropic or asymmetric "microfin" actuating structures, and by inducing thickness gradients in the hydrogel using laminar flow in microfluidic channels. Their unique topography can be designed to confer a wide range of optical, wetting, adhesive, anti-bacterial, motion-generating, and other behaviors, similar to their natural counterparts used by lotus leaves to shed water, geckos to stick to surfaces, echinoderms to keep their skin clean, and fish to sense flow. An additional beauty of these nanostructured surfaces is that any of these properties can be switched or fine-tuned just by bending or tilting the structures to alter the patterns. To harvest and channel energy to drive such reconfigurations, we embed the nanostructures in hydrogels that can be chemically tailored to sense a wide selection of chemical, mechanical, humidity, temperature, light, biochemical, and other environmental conditions. Changes in these conditions cause the gel to swell or contract, generating not only the mechanical energy of bulk size change but an entire multiscale, 3D cooperative network of mechanical forces within the gel that provide the work for reconfiguring the nanostructures. Using both experimental and modeling approaches as well as new fabrication methods, we are developing our ability to take full advantage of the immense potential for energy coupling within these hybrids to create a generation of sustainable, self-reporting, self-adapting materials. ## Projects [### SMARTS: Self-regulating Artificial Material Systems ](/smarts-self-regulating-artificial-material-systems) ![nature_cover_6-crop.jpg](/sites/g/files/omnuum6296/files/styles/hwp_16_9__480x270/public/aizenberg/files/nature_cover_6-crop.jpg?itok=N-Sb-mz4) [### Reversible switching of surface wettability ](/reversible-switching-surface-wettability) ![switchwet1a.jpg](/sites/g/files/omnuum6296/files/styles/hwp_16_9__480x270/public/aizenberg/files/switchwet1a.jpg?itok=zNo4QUZh) [### Submerged HAIRS actuated by pH ](/submerged-hairs-actuated-ph) ![hairsmicrofluidic_1.jpg](/sites/g/files/omnuum6296/files/styles/hwp_16_9__480x270/public/aizenberg/files/hairsmicrofluidic_1.jpg?itok=IwYFCdSZ) Publications In the News ## Publications Download 34 citations download- [BibTeX](/bibcite/export?pager_style=standard_pager&number_of_items=6&sort_field=bibcite_year--desc&taxonomy_filters%5Bfield_hwp_c_affiliated_authors%5D&taxonomy_filters%5Bfield_hwp_c_project%5D&taxonomy_filters%5Bfield_hwp_c_publicationgroupaffi%5D&taxonomy_filters%5Bfield_hwp_c_researchtopics12%5D%5B0%5D%5Btarget_id%5D=106061&taxonomy_filters%5Bfield_hwp_c_year123456%5D&&&format=bibtex) - [EndNote X3 XML](/bibcite/export?pager_style=standard_pager&number_of_items=6&sort_field=bibcite_year--desc&taxonomy_filters%5Bfield_hwp_c_affiliated_authors%5D&taxonomy_filters%5Bfield_hwp_c_project%5D&taxonomy_filters%5Bfield_hwp_c_publicationgroupaffi%5D&taxonomy_filters%5Bfield_hwp_c_researchtopics12%5D%5B0%5D%5Btarget_id%5D=106061&taxonomy_filters%5Bfield_hwp_c_year123456%5D&&&format=endnote8) - [EndNote 7 XML](/bibcite/export?pager_style=standard_pager&number_of_items=6&sort_field=bibcite_year--desc&taxonomy_filters%5Bfield_hwp_c_affiliated_authors%5D&taxonomy_filters%5Bfield_hwp_c_project%5D&taxonomy_filters%5Bfield_hwp_c_publicationgroupaffi%5D&taxonomy_filters%5Bfield_hwp_c_researchtopics12%5D%5B0%5D%5Btarget_id%5D=106061&taxonomy_filters%5Bfield_hwp_c_year123456%5D&&&format=endnote7) - [Endnote tagged](/bibcite/export?pager_style=standard_pager&number_of_items=6&sort_field=bibcite_year--desc&taxonomy_filters%5Bfield_hwp_c_affiliated_authors%5D&taxonomy_filters%5Bfield_hwp_c_project%5D&taxonomy_filters%5Bfield_hwp_c_publicationgroupaffi%5D&taxonomy_filters%5Bfield_hwp_c_researchtopics12%5D%5B0%5D%5Btarget_id%5D=106061&taxonomy_filters%5Bfield_hwp_c_year123456%5D&&&format=tagged) - [Marc](/bibcite/export?pager_style=standard_pager&number_of_items=6&sort_field=bibcite_year--desc&taxonomy_filters%5Bfield_hwp_c_affiliated_authors%5D&taxonomy_filters%5Bfield_hwp_c_project%5D&taxonomy_filters%5Bfield_hwp_c_publicationgroupaffi%5D&taxonomy_filters%5Bfield_hwp_c_researchtopics12%5D%5B0%5D%5Btarget_id%5D=106061&taxonomy_filters%5Bfield_hwp_c_year123456%5D&&&format=marc) - [PubMedId](/bibcite/export?pager_style=standard_pager&number_of_items=6&sort_field=bibcite_year--desc&taxonomy_filters%5Bfield_hwp_c_affiliated_authors%5D&taxonomy_filters%5Bfield_hwp_c_project%5D&taxonomy_filters%5Bfield_hwp_c_publicationgroupaffi%5D&taxonomy_filters%5Bfield_hwp_c_researchtopics12%5D%5B0%5D%5Btarget_id%5D=106061&taxonomy_filters%5Bfield_hwp_c_year123456%5D&&&format=pubmed_id) - [RIS](/bibcite/export?pager_style=standard_pager&number_of_items=6&sort_field=bibcite_year--desc&taxonomy_filters%5Bfield_hwp_c_affiliated_authors%5D&taxonomy_filters%5Bfield_hwp_c_project%5D&taxonomy_filters%5Bfield_hwp_c_publicationgroupaffi%5D&taxonomy_filters%5Bfield_hwp_c_researchtopics12%5D%5B0%5D%5Btarget_id%5D=106061&taxonomy_filters%5Bfield_hwp_c_year123456%5D&&&format=ris) ### 2023 Thaggard GC, Park KC, Lim J, Kankanamalage BKPM, Haimerl J, Wilson GR, McBride MK, Forrester KL, Adelson ER, Arnold VS, et al. [Breaking the photoswitch speed limit.](/publication/breaking-photoswitch-speed-limit) Nature communications. 2023;14(1):7556. doi:10.1038/s41467-023-43405-w Thaggard GC, Park KC, Lim J, Kankanamalage BKPM, Haimerl J, Wilson GR, McBride MK, Forrester KL, Adelson ER, Arnold VS, et al. [Breaking the photoswitch speed limit.](/publication/breaking-photoswitch-speed-limit) Nature communications. 2023;14(1):7556. doi:10.1038/s41467-023-43405-w - add\_circle\_outline do\_not\_disturb\_on Abstract The forthcoming generation of materials, including artificial muscles, recyclable and healable systems, photochromic heterogeneous catalysts, or tailorable supercapacitors, relies on the fundamental concept of rapid switching between two or more discrete... Zhou X, Zheng Y, Zhang H, Yang L, Cui Y, Krishnan BP, Dong S, Aizenberg M, Xiong X, Hu Y, et al. [Reversibly growing crosslinked polymers with programmable sizes and properties.](/publication/reversibly-growing-crosslinked-polymers-programmable-sizes-and-properties) Nature communications. 2023;14(1):3302. doi:10.1038/s41467-023-38768-z Zhou X, Zheng Y, Zhang H, Yang L, Cui Y, Krishnan BP, Dong S, Aizenberg M, Xiong X, Hu Y, et al. [Reversibly growing crosslinked polymers with programmable sizes and properties.](/publication/reversibly-growing-crosslinked-polymers-programmable-sizes-and-properties) Nature communications. 2023;14(1):3302. doi:10.1038/s41467-023-38768-z - add\_circle\_outline do\_not\_disturb\_on Abstract Growth constitutes a powerful method to post-modulate materials' structures and functions without compromising their mechanical performance for sustainable use, but the process is irreversible. To address this issue, we here report a growing-degrowing... ### 2022 Liu Y, Zhang CT, Aizenberg J, Balazs AC. [Control over emergence and alignment of transient blisters in thermo-responsive gels using hierarchically patterned substrates.](/publication/control-over-emergence-and-alignment-transient-blisters-thermo-responsive-gels-using) Soft matter. 2022;18(32):6032–6042. doi:10.1039/d2sm00579d Liu Y, Zhang CT, Aizenberg J, Balazs AC. [Control over emergence and alignment of transient blisters in thermo-responsive gels using hierarchically patterned substrates.](/publication/control-over-emergence-and-alignment-transient-blisters-thermo-responsive-gels-using) Soft matter. 2022;18(32):6032–6042. doi:10.1039/d2sm00579d - add\_circle\_outline do\_not\_disturb\_on Abstract Surfaces with tunable microscale textures are vital in a large variety of technological applications, including heat transfer, antifouling and adhesion. To facilitate such broad-scale use, there is a need to create surfaces that undergo reconfigurable... Meeks A, Lerch MM, Schroeder TBH, Shastri A, Aizenberg J. [Spiropyran Photoisomerization Dynamics in Multiresponsive Hydrogels.](/publication/spiropyran-photoisomerization-dynamics-multiresponsive-hydrogels) Journal of the American Chemical Society. 2022;144(1):219–227. doi:10.1021/jacs.1c08778 Meeks A, Lerch MM, Schroeder TBH, Shastri A, Aizenberg J. [Spiropyran Photoisomerization Dynamics in Multiresponsive Hydrogels.](/publication/spiropyran-photoisomerization-dynamics-multiresponsive-hydrogels) Journal of the American Chemical Society. 2022;144(1):219–227. doi:10.1021/jacs.1c08778 - add\_circle\_outline do\_not\_disturb\_on Abstract Light-responsive, spiropyran-functionalized hydrogels have been used to create reversibly photoactuated structures for applications ranging from microfluidics to nonlinear optics. Tailoring a spiropyran-functionalized hydrogel system for a particular... ### 2021 Li, Librandi, Yao, Richard, Yamamura A, Aizenberg, Bertoldi K. [Controlling Liquid Crystal Orientations for Programmable Anisotropic Transformations in Cellular Microstructures](https://onlinelibrary.wiley.com/doi/epdf/10.1002/adma.202105024). Advanced Materials. 2021:2105024. doi:10.1002/adma.202105024 Li, Librandi, Yao, Richard, Yamamura A, Aizenberg, Bertoldi K. [Controlling Liquid Crystal Orientations for Programmable Anisotropic Transformations in Cellular Microstructures](https://onlinelibrary.wiley.com/doi/epdf/10.1002/adma.202105024). Advanced Materials. 2021:2105024. doi:10.1002/adma.202105024 - add\_circle\_outline do\_not\_disturb\_on Abstract Geometric reconfigurations in cellular structures have recently been exploited to realize adaptive materials with applications in mechanics, optics, and electronics. However, the achievable symmetry breakings and corresponding types of deformation and... ### 2017 Sutton, Shirman, Timonen J, England G, Kim, Kolle, Ferrante, Zarzar L, Strong, Aizenberg. [Photothermally triggered actuation of hybrid materials as a new platform for in vitro cell manipulation](/publications/photothermally-triggered-actuation-hybrid-materials-new-platform-vitro-cell). Nat. Commun. 2017;8:14700. Sutton, Shirman, Timonen J, England G, Kim, Kolle, Ferrante, Zarzar L, Strong, Aizenberg. [Photothermally triggered actuation of hybrid materials as a new platform for in vitro cell manipulation](/publications/photothermally-triggered-actuation-hybrid-materials-new-platform-vitro-cell). Nat. Commun. 2017;8:14700. - add\_circle\_outline do\_not\_disturb\_on Abstract - [ descriptionPublisher's Version](http://nrs.harvard.edu/urn-3:HUL.InstRepos:32094141) 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... - [ descriptionPublisher's Version](http://nrs.harvard.edu/urn-3:HUL.InstRepos:32094141) - Previous page chevron\_left - [1](?page=0%2C0 "Current page") - [2](?page=1%2C0 "Go to page 2") - [3](?page=2%2C0 "Go to page 3") - [4](?page=3%2C0 "Go to page 4") - [5](?page=4%2C0 "Go to page 5") - [6](?page=5%2C0 "Go to page 6") - [ Next page chevron\_right ](?page=1%2C0 "Go to next page") ## In the News [Biomolecules Sorted with Catch-and-Release System](http://www.genengnews.com/gen-news-highlights/biomolecules-sorted-with-catch-and-release-system/81251065/), Genetic Engineering & Biotechnology News, March 24, 2015. [Catching and releasing tiny molecules](http://www.seas.harvard.edu/news/2015/03/catching-and-releasing-tiny-molecules), Harvard press release, March 23, 2015. [Lifelike cooling for sunbaked windows](http://wyss.harvard.edu/viewpressrelease/119/), Wyss Institute press release, July 30, 2013. [Hydrogels: The catalytic curtsey](http://www.nature.com/nmat/journal/v11/n8/full/nmat3381.html?WT.ec_id=NMAT-201208), Nature Materials, July 24, 2012. [Materials with SMARTS](http://cen.acs.org/articles/90/i29/Materials-SMARTS.html), Chemical & Engineering News, July 16, 2012. [Nanomaterial duplicates self-regulation of living organisms](http://spectrum.ieee.org/nanoclast/semiconductors/nanotechnology/nanomaterial-duplicates-selfregulation-of-living-organisms), IEEE Spectrum, July 13, 2012. [New SMART materials regulate, respond to their environment](http://www.txchnologist.com/2012/new-smart-materials-regulate-respond-to-their-environment), Txchnologist, July 12, 2012. [Homeostatic hydrogels to help heat the home](http://www.rsc.org/chemistryworld/2012/07/homeostatic-hydrogels), Chemistry World, July 12, 2012. [Smart buildings](http://www.nature.com/multimedia/podcast/nature/v487/n7406/nature-2012-07-12.mp3), Nature's weekly podcast (at 06:49), July 12, 2012. [Smart materials get SMARTer](http://www.seas.harvard.edu/news-events/press-releases/smart-materials-get-smarter), Harvard press release, July 11, 2012.