SUPER-WATER-REPELLENT FRACTAL SURFACES

Wettability of fractal surfaces has been studied both theoretically an d experimentally. The contact angle of a liquid droplet placed on a fr actal surface is expressed as a function of the fractal dimension, the range of fractal behavior, and the contacting ratio of the surface. T he result shows that fractal surfaces can be super water repellent (su perwettable) when the surfaces are composed of hydrophobic (hydrophili c) materials. We also demonstrate a super-water-repellent fractal surf ace made of alkylketene dimer; a water droplet on this surface has a c ontact angle as large as 174 degrees.