Nanonails - a Simple Geometrical Approach to Superlyophobic Surfaces

In this paper we propose a novel approach that can greatly enhance our ability to control the behavior of liquids on solid substrates. We experimentally demonstrate this approach by transforming ordinary fluoropolymer surfaces into "superlyophobic" substrates that completely repel an extremely broad range of liquids, with surface tensions extending from 72 mN/m (water) to 21.8 mN/m (ethanol). The proposed approach is simple, highly effective, and very general. It relies on a new type of three- dimensional nano-scale surface topography, which allows us to "lock" the liquid in a desirable metastable state, and thus dramatically extends the range of options available to achieve a required liquid behavior. We hope that this approach, coupled with the recent advances in nanofabrication, will open the way to the development of a wide variety of novel materials with applications ranging from sensors and microfluidics to contamination-resistant coatings and drag-reducing surfaces.