Apparent Contact Angles on Lubricant-Impregnated Surfaces/SLIPS: From Superhydrophobicity to Electrowetting

• DOI: 10.1021/acs.langmuir.8b04136
• Publication Date: 2019-02-13T23:25:58Z
• Authors: Glen McHale; Bethany V. Orme; Gary G. Wells; Rodrigo Ledesma-A...
• Keywords: Wetting transition; Texture (cosmology)

A fundamental limitation of liquids on many surfaces is their contact line pinning. This can be overcome by infusing a nonvolatile and immiscible liquid or lubricant into the texture roughness created in applied onto solid substrate so that interest no longer directly contacts underlying surface. Such slippery liquid-infused porous (SLIPS), also known as lubricant-impregnated surfaces, completely remove pinning angle hysteresis. However, although sessile droplet may rest such surface, its only an apparent because now with second not solid. Close to solid, has wetting ridge force balance liquid-liquid liquid-vapor interfacial tensions described Neumann's triangle rather than Young's law. Here, we show how, provided coating thin small, surface free energy approach used obtain equation analogous law using for lubricant-vapor liquid-lubricant effective tension combined liquid-lubricant-vapor interfaces. sum positive negative spreading power liquid, respectively. Using this approach, then how Cassie-Baxter, Wenzel, hemiwicking, other equations rough, textured complex geometry electrowetting dielectrowetting replaced from equivalent smooth The resulting are consistent literature data. These results enable equilibrium theory droplets widely retain conformal SLIPS coating.