Biomimetic hierarchical structure for self-cleaning

Hierarchical roughness is beneficial for superhydrophobicity. Surfaces with microstructure, nanostructure, and hierarchical structure were fabricated by replication of micropattern and self- assembly of hydrophobic alkanes. The fabrication technique used is a low cost two step process, which provides flexibility in the fabrication of a variety of hierarchical structures. Fabricated structures and surface chemistry mimic the hierarchical surfaces of superhydrophobic and self-cleaning plant surfaces. The influence of structure on superhydrophobicity at different length scales is demonstrated by the investigation of static contact angle, hysteresis and tilt angles, and propensity of air pocket formation as well as adhesive forces. (C) 2008 American Institute of Physics.