Kyung-In Jang1, Ha Uk Chung1, Sheng Xu1, Chi Hwan Lee1, Haiwen Luan2, Jaewoong Jeong3, Huanyu Cheng2, Gwang-Tae Kim1, Sang Youn Han1,4, Jung Woo Lee1,5, Jeonghyun Kim1,5, Moongee Cho1, Fuxing Miao2,6, Yiyuan Yang1, Han Na Jung1, Matthew Flavin1, Howard Liu1, Gil Woo Kong1, Ki Jun Yu1, Sang Il Rhee1, Jeahoon Chung1, Byunggik Kim1, Jean Won Kwak1, Myoung Hee Yun1,7, Jin Young Kim7, Young Min Song8, Ungyu Paik5, Yihui Zhang2,9, Yonggang Huang2 & John A. Rogers1
1 Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana-Champaign, Urbana, Illinois 61801, USA. 2 Department of Civil and Environmental Engineering, Department of Mechanical Engineering, Center for Engineering and Health and Skin Disease Research Center, Northwestern University, Evanston, Illinois 60208, USA. 3 Department of Electrical, Computer and Energy Engineering, University of Colorado, Boulder, Colorado 80309, USA. 4 Samsung Display Co. Display R&D Center, Yongin-city, Gyeongki-do 446–711, Republic of Korea. 5 Department of Material Science and Engineering, Department of Energy Engineering, Hanyang University, Seoul 133-791, Republic of Korea. 6 Department of Mechanical Engineering and Mechanics, Ningbo University, Ningbo 315211, China. 7 School of Energy and Chemical Engineering, Ulsan National Institute Science and Technology (UNIST), Ulsan 689-798, Republic of Korea. 8 Department of Electronic Engineering, Biomedical Research Institute, Pusan National University, Geumjeong-gu, Busan 609-735, Republic of Korea. 9 Center for Mechanics and Materials, Tsinghua University, Beijing 100084, China.
Correspondence and requests for materials should be addressed to Y.Z. or to Y.H. or to J.A.R..
Hard and soft structural composites found in biology provide inspiration for the design of advanced synthetic materials. Many examples of bio-inspired hard materials can be found in the literature; far less attention has been devoted to soft systems. Here we introduce deterministic routes to low-modulus thin film materials with stress/strain responses that can be tailored precisely to match the non-linear properties of biological tissues, with application opportunities that range from soft biomedical devices to constructs for tissue engineering. The approach combines a low-modulus matrix with an open, stretchable network as a structural reinforcement that can yield classes of composites with a wide range of desired mechanical responses, including anisotropic, spatially heterogeneous, hierarchical and self-similar designs. Demonstrative application examples in thin, skin-mounted electrophysiological sensors with mechanics precisely matched to the human epidermis and in soft, hydrogel-based vehicles for triggered drug release suggest their broad potential uses in biomedical devices.