Reversible superhydrophilicity and superhydrophobicity on a lotus-leaf pattern.

A facile approach of fabricating a temperature-responsive coating capable of switching reversibly from being superhydrophobic to superhydrophilic is presented. The approach combines micromolding, layer-by-layer assembly of the polymer macroinitiators, and surface-initiated polymerization. Changing between superhydrophobicity and superhydrophilicity depends heavily on the surface roughness and the switching of the surface energy levels. In this study, surface roughness was introduced by replicating the surface morphology of a lotus leaf. The switching of surface energy levels was made possible by grafting a temperature-responsive polymer brush. Wetting studies reveal that the reported approach not only replicates nature but also improves its property by making it responsive to stimulus.