Reversible Switching of Surface Wettability and Water Adhesion on a Polymer Nano-composite Coating

Abstract

Super-hydrophobic polymer/ZnO nano-composite coatings were fabricated by a simple spray-coating method. When the prepared super-hydrophobic coating was directly illuminated by UV light, the surface was fully covered with the hydrophilic groups, which created a state of super-hydrophilic wettability. When UV light illuminated the surface through a mask, the surface maintained its super-hydrophobic property, but the adhesion of a water droplet changed from sliding easily to a highly sticky movement. More importantly, the initial surface wettability and water adhesion can be re-established by heat treatment, and these processes were repeated, with full reproducibility, for a number of cycles.