Compact nanoscale textures reduce contact time of bouncing droplets
Many natural surfaces can rapidly shed water droplets due to their water-repellent functionality. In 1945, scientists Cassie and Baxter linked the water-repellent function of natural surfaces to their surface textures. The use of low solid fraction textures (denoted Φs) is therefore a key principle to design water-repellent surfaces. In this work, Lin Wang and a team of scientists in materials science, biomedical engineering and mechanical engineering at the Pennsylvania State University, U.S. reduced the contact time of bouncing droplets on high solid fraction surfaces (i.e. Φs ~ 0.25 to 0.65) by reducing the surface texture size to the nanoscale. They showed how high solid fraction surfaces with a texture size below 100 nanometers could reduce the contact time of bouncing droplets by approximately 2.6 milliseconds (ms) compared to a texture size above 300 nm. The texture and size-dependent contact time reduction observed on solid surfaces is a first-in-study outcome relative...