Progress in Superhydrophilic Surface Development

Superhydrophilic surfaces induce the complete spreading of a water droplet to near-zero contact angle. This extreme water-loving behavior makes such surfaces favorable for a broad range of research and commercial applications. Superhydrophilicity can be induced by surface structure, specifically by rough and porous microstructures. Surface reactions based on photo-induced mechanism enhance the superhydrophilic effect of surfaces with microstructures. In this review, the generation of porous and rough surfaces exhibiting superhydrophilicity using various techniques such as etching, layer-by-layer assembly, hydrothermal treatment, nanocomposite coatings and polymerization are summarized. Furthermore, techniques for creating superhydrophilic coatings comprising light-sensitive materials are described. We also discuss the fundamental challenges involved in generating robust superhydrophilic surfaces.