Hydrophobic self-cleaning surfaces of ZnO thin films synthesized by sol–gel technique

Abstract

The authors report on hydrophobic self-cleaning surfaces of transparent zinc oxide (ZnO) thin films tuned by controlling uniformity of the film surfaces. ZnO films were synthesized by a simple, low-cost sol–gel technique. The degree of hydrophobicity of the films was strongly dependent on the number of coatings with ZnO. The surface of the polycrystalline ZnO thin film with 8-coatings was maximum hydrophobic with a static contact angle of 114° ± 3°. The films were highly transparent with average transmission exceeding 80% in the visible region. Thus, new hydrophobic ZnO thin films can be of great importance in commercial application as transparent self-cleaning surfaces.