Fabrication of a fluorine-free photocatalytic superhydrophobic coating and its long-lasting anticorrosion and excellent antibacterial abilities

Superhydrophobic multifunctional coatings have wide application prospects in construction, shipping, transportation equipment and aerospace etc. In this paper, a fluorine-free photocatalytic superhydrophobic coating with long-lasting anticorrosion performance and excellent antibacterial ability has been developed on various substrates by a simple spraying method. The coating is mainly composed of epoxy resin (EP), polydimethylsiloxane (PDMS) and hydrophobically modified micron ZnO (m-ZnO) and nano ZnO (n-ZnO). The coating maintains excellent wettability to various common liquids, and the water contact angle (WCA) and sliding angle (SA) of coating are 162.8° and 3°, respectively. The synergistic effect of the air layers and the coating denseness endows coating with excellent corrosion inhibition efficiency (ηp > 99.9 %) in 3.5 wt% NaCl solution and neutral salt spray tests for 30 days. The photocatalytic activity and superhydrophobicity endow coating with bactericidal activity and antibacterial adhesion properties, thus providing the coating with excellent antibacterial ability in dynamic or static liquid environment. Furthermore, the coating can withstand chemical erosion, ultraviolet radiation and mechanical durability tests such as knife scraping, tape peeling and sandpaper wear cycles. This large-scale fabrication, environmentally benign, low cost and high performance coating has potential practical applications in a wider range of fields.