Controlling the direction and amount of a splash with textured surface

Abstract

Because splashing is such a violent process, one might naively expect that neither the direction of droplet emission nor the amount of ejected material can be controlled with any precision. Even though it is observed countless times in the course of a day, drop splashing is highly non-intuitive: for example, it is surprising that the surrounding air pressure determines whether a drop will splash when hitting a smooth surface. Here we describe a discovery with significant practical ramifications: the direction, as well as the number, of the ejected droplets can be controlled by the texture of a surface.