Spray-on omniphobic ZnO coatings

Abstract

In recent years, the design of highly liquid-repellent surfaces has received great attention. Here, we report a facile method of creating a surface that repels both water and oils; using simple spray-coating, a hierarchically rough ZnO–PDMS composite can be applied to a variety of substrates that serves as a nanostructured surface for further modification. We applied an overcoating of either a fluoropolymer (Teflon AF) or perfluorodecyltrichlorosilane to fabricate low energy surfaces that repel water and oil for a variety of potential uses. The resultant surfaces are superomniphobic, have static contact angles of >140° for droplets of both liquids, and have low sliding angles for both water and oil droplets: <5° for water and <20° for oil.