A research team affiliated with UNIST has examined the rates of liquid penetration on rough or patterned surfaces, especially those with pores or cavities. Their findings provide important insights into the development of everyday products, including cosmetics and paints, and industrial applications like enhanced oil recovery.
This study has been jointly led by Professor Dong Woog Lee and his research team in the School of Energy and Chemical Engineering at UNIST and a research team at the University of California, Santa Barbara. Published online in the July 19th issue of the Proceedings of the National Academy of Sciences (PNAS), the study identifies five variables that control cavity-filling (wetting transition) rates, required for liquids to penetrate into cavities.
In the study, Professor Lee fabricated silicon wafers with cylindrical cavities of different geometries. After immersing them in bulk water, they observed the details of, and the rates associated with, water penetration into the cavities from the bulk, using bright-field and confocal fluorescence microscopy. Cylindrical cavities are like skin pores with narrow entrance and specious interior. The cavity filling generally progresses when bulk water is spread above a hydrophilic, reentrant cavity. As described in “Wetting Transition from the Cassie-Baxter State to Wenzel State,” the […]