S3E9
Episode 9 (March 14, 2021)
Kun-Hao Yu
University of Southern California
Lin Wang
Penn State University
Additive Manufacturing and Mechanics of Photosynthesis-assisted polymer remodeling
Abstract of Talk 1
Living creatures are continuous sources of inspiration for designing engineering materials and structures. However, synthetic engineering materials are typically different from living creatures, because the latter consist of living cells to support their metabolisms, such as remodeling, growth, and reproduction. How to harness living cells to metabolize synthetic engineering materials remains largely elusive. We report an attempt to exploit living chloroplasts to metabolize three-dimensional-printed polymers. With living chloroplasts and synthetic polymers, the system leads to a class of hybrid synthetic-living materials whose microstructures and properties can be remodeled on-demand by the photosynthesis of chloroplasts. In addition, we proposed a theoretical model to understand photosynthesis-assisted strengthening behaviors of polymers.
Biosketch of Speaker 1
Kun-Hao Yu is a Ph.D. candidate in the Department of Civil and Environmental Engineering at University of Southern California (USC). He received his B.S. degree in Civil Engineering from National Central University in 2014, and his S.M. in the Department of Civil and Environmental Engineering at USC. He joined Professor Qiming Wang’s group at USC in 2016 and he’s current research is focused on understanding and exploiting interesting characteristics of bioinspired materials and structures through fundamental mechanics and advanced manufacturing.
Compact Bio-Inspired Nanoscale Textures Reduce Contact Time of Bouncing Droplets
Abstract of Talk 3
Many natural surfaces are capable of rapidly shedding water droplets – a phenomenon that has been attributed to the presence of low solid fraction textures (Φs ~ 0.01). However, recent observations revealed the presence of unusually high solid fraction nanoscale textures (Φs ~ 0.25 – 0.64) on water-repellent insect surfaces, which cannot be explained by existing wetting theories. Here we show that the contact time of bouncing droplets on high solid fraction surfaces can be reduced by reducing the texture size to ~100 nanometers. We demonstrated that the texture-size dependent contact time reduction could be attributed to the dominance of line tension on nanotextures, and that compact arrangement of nanotextures is essential to withstand the impact pressure of raindrops. Our findings illustrate a potential survival strategy adopted by insects to rapidly shed impacting raindrops, and suggest a previously unidentified design principle to engineering robust water-repellent materials for applications including miniaturized drones.
Biosketch of Speaker 3
Biosketch: Dr. Lin Wang is a postdoctoral scholar in the Department of Mechanical Engineering at The Pennsylvania State University, University Park. He received his Ph.D. in Materials Science and Engineering from The Pennsylvania State University, University Park in 2020. His Ph.D. advisor is Prof. Tak-Sing Wong. He received his B.S. in Chemistry from the Beihang University in 2013. He is the recipient of the Nanoscale Science and Technology Division Graduate Student Award from the American Vacuum Society (2020). His research interests focus on bio-inspired functional materials.
Guest Host: Jing Wang
Dr. Jing Wang is currently a postdoctoral fellow in the Department of Mechanical Engineering at The University of Michigan, Ann Arbor (with Prof. Neil Dasgupta and Prof. Anish Tuteja). He received his Ph.D. degree as a PPG Industries Foundation Ph.D. Fellow (2014) in the Mechanical and Nuclear Engineering Department at The Pennsylvania State University in 2018 (with Prof. Tak Sing Wong), following his B.Eng. degree in Measurement, Control Technology and Instruments from Tsinghua University. Dr. Wang's research focuses on surface and interface science and engineering, micro/nano manufacturing, and biologically inspired engineering with applications in materials science, phase-change heat transfer, water saving and desalination, biomedical devices, and energy saving and extraction. His research has collectively led to 8 granted and pending US and international patents, as well as 10 peer-reviewed publications, including papers in Nature Sustainability, Nature Communications, Science Advances, and Advanced Materials. Many of these research works have been featured by the media worldwide, such as BBC, The Times, The Economist, Scientific American, Science, Nature Materials, and more. One of his inventions (LESS coating technology) have been commercialized by a start-up company (SpotLESS Materials Inc.).