We investigate the science and technology of mechanics-driven manufacturing, particularly at small scales (in the nano-micro-millimeter regime). Advanced manufacturing technologies at these length scales play crucial roles in addressing grand challenges in energy, environment, and healthcare. We aim to transform manufacturing capabilities in these contexts, through mechanics-driven, multidisciplinary approaches (e.g. self-assembly, strain engineering, transfer printing, etc.) that involve mechanics, materials science, interfacial science, electronics, and others. Our focus areas include 3D assembly of functional materials, micro/nano-engineered surfaces, flexible electronics, and smart materials and structures. The following sections highlight some of these efforts.
3D Multiscale Soft Electronics
The growing availability of 3D manufacturing methods has implications across diverse applications, from ship building to microelectronics processing. Systems with sizes in the nano-micro-millimeter regime are of particular interest, where few techniques offer the necessary range of capabilities in throughput, material compatibility, and design versatility. We overcome these limitations by using mechanically guided 3D assembly approaches to manufacturing 3D structures and soft electronics in high-performance functional materials for a wide range of applications, including reconfigurable electronics/optoelectronics, sensors, biomedical devices, and microrobotics.
Examples of 3D soft meso- and microscale electronics fabricated by mechanically guided assembly.
Selected publications:
X. Huang, L. Liu, Y.H. Lin, R. Feng, Y. Shen, Y. Chang, H. Zhao, “High-stretchability and low-hysteresis strain sensors using origami-inspired 3D mesostructures“, Science Advances, 9, eadh9799, 2023.
H. Zhao, Y. Kim, H. Wang, X. Ning, C. Xu, J. Suh, M. Han, G.J. Pagan-Diaz, W. Lu, H. Li, W. Bai, O. Aydin, Y. Park, J. Wang, Y. Yao, Y. He, M.T.A. Saif, Y. Huang, R. Bashir, J.A. Rogers, “Compliant 3D frameworks instrumented with strain sensors for characterization of millimeter-scale engineered muscle tissues“, Proceedings of the National Academy of Sciences (PNAS), 118, e2100077118, 2021.
H. Zhao, K. Li, M. Han, F. Zhu, A. Vázquez-Guardado, P. Guo, Z. Xie, Y. Park, L. Chen, X. Wang, H. Luan, Y. Yang, H. Wang, C. Liang, Y. Xue, R.D. Schaller, D. Chanda, Y. Huang, Y. Zhang, J.A. Rogers, “Buckling and twisting of advanced materials into morphable 3D mesostructures”, Proceedings of the National Academy of Sciences (PNAS), 116, 13239-13248, 2019.
H. Zhao, Y. Lee, M. Han, B.K. Sharma, X. Chen, J.-H. Ahn, J.A. Rogers, “Nanofabrication approaches for functional three-dimensional architectures”, Nano Today, 30, 100825, 2020.
Flexible and Stretchable Electronics
Advances in mechanics and materials provide routes to electronics that can bend, stretch, twist, and deform into complex, curvilinear shapes while maintaining functionalities of conventional wafer-based systems. Such flexible and stretchable electronics can overcome manifold mismatch between soft biological systems and conventional electronics. We focus on fundamental and applied research on flexible and stretchable electronics, including physical and chemical sensors, actuators, and computing devices.
Examples of flexible and stretchable electronic sensors and devices.
Selected publications:
H. Zhang, H. Zhao, X. Zhao, C. Xu, D. Franklin, A.Vázquez-Guardado, W. Bai, J. Zhao, K. Li, G. Monti, W. Lu, A. Kobeissi, L. Tian, X. Ning, X. Yu, S. Mehta, D. Chanda, Y. Huang, S. Xu, B. E. Perez White, J.A. Rogers, “Biocompatible light guide-assisted wearable devices for enhanced UV light delivery in deep skin“, Advanced Functional Materials, 31, 2100576, 2021.
M. Han, L. Chen, K. Aras, C. Liang, X. Chen, H. Zhao, K. Li, N.R. Faye, B. Sun, J.-H. Kim, W. Bai, Q. Yang, Y. Ma, W. Lu, E. Song. J.M. Baek. Y. Lee, C. Liu, J.B. Model, G. Yang, R. Ghaffari, Y. Huang, I.R. Efimov, J.A. Rogers, “Catheter-integrated soft multilayer electronic arrays for multiplexed sensing and actuation during cardiac surgery”, Nature Biomedical Engineering, 4, 997-1009, 2020.
Engineered Surfaces and Interfaces
Engineering of surfaces and interfaces is of great fundamental and practical interest. The ability to control processes such as wetting, adhesion, and transport on surfaces has a wide range of applications including phase change heat transfer, self-cleaning surfaces, advanced sensors, and microfluidic devices. We focus on developing innovative manufacturing methods for producing engineered surfaces and interfaces with bioinspired, complex architecture and surface properties for engineering applications.
Selected publications:
H. Zhao, S. Park, B.R. Solomon, S. Kim, D. Soto, A.T. Paxson, K.K. Varanasi, A.J. Hart, “Synthetic butterfly scale surfaces with compliance-tailored anisotropic droplet adhesion”, Advanced Materials, 31, 1807686, 2019.
H. Zhao, S. Dash, N.S. Dhillon, S. Kim, B. Lettiere, K.K. Varanasi, A.J. Hart, “Microstructured ceramic-coated carbon nanotube surfaces for high heat flux pool boiling”, ACS Applied Nano Materials, 2, 5538-5545, 2019.
H. Zhao, C. Jacob, H.A. Stone, A. J. Hart, “Liquid imbibition in ceramic-coated carbon nanotube films”, Langmuir, 32, 12686-12692, 2016.
Stimuli-Responsive Materials and Devices
Materials and structures that adapt their shapes in response to external stimuli hold immense promise for applications in optics, robotics, and biomedical engineering. We aim to advance the design and manufacturing of stimuli-responsive materials and devices toward intelligent systems.
Selected publications:
H. Zhao, J.J. Wie, D. Copic, C.R. Oliver, A. Orbaek White, S. Kim, A. J. Hart, “High-fidelity replica molding of glassy liquid crystalline polymer microstructures”, ACS Applied Materials & Interfaces, 8, 8110-8117, 2016.
J. Jeon, J.E. Park, S.J. Park, S. Won, H. Zhao, S. Kim, B.S. Shim, A. Urbas, A.J. Hart, Z. Ku, J.J. Wie, “Shape-programmed fabrication and actuation of magnetically active micropost arrays”, ACS Applied Materials & Interfaces, 12, 17113-17120, 2020.