Postdoctoral Fellow, Penn State
Presented: February 25 and 26, 2021
“Compact bio-inspired nanoscale textures reduce contact time of bouncing droplets”
Many natural surfaces are capable of rapidly shedding water droplets—a phenomenon that has been attributed to the presence of low solid fraction textures (fs ~ 0.01). However, recent observations revealed the presence of unusually high solid fraction nanoscale textures (fs ~ 0.25 to 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 nm. 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 of insects to rapidly shed impacting raindrops, and suggest a previously unidentified design principle to engineering robust water-repellent materials for applications including miniaturized drones.
Lin Wang, Postdoctoral Fellow, Penn State
Lin Wang is a postdoctoral fellow at the Department of Mechanical Engineering and Materials Research Institute, Penn State University, University Park. He received his Ph.D. degree in 2020 from Penn State University, University Park, in materials science and engineering. His Ph.D. advisor is Dr. Tak-Sing Wong. 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.