Aerosol-assisted chemical vapour deposition of transparent superhydrophobic film by using mixed functional alkoxysilanes.

A method for the preparation of transparent superhydrophobic silica coatings on glass substrates via aerosol-assisted chemical vapour deposition (AACVD) is described. A multi-layer process to produce dual scale silica nanoparticles films, by using different functional alkoxysilanes was investigated. A first layer of 3-methacryloxypropyltrimethoxysilane (MPS) and a second layer of tetraethylorthosilicate (TEOS) were deposited at different temperatures to generate micro and nano particles of silica. Finally, a layer of perfluorooctyltriethoxysilane was deposited on top of the two layers to achieve superhydrophobicity. The transparent superhydrophobic film showed transparency of 90% in the visible light region with a static water contact angle of 165° and a sliding angle lower than 1°. Various durability tests were performed on the transparent superhydrophobic film, showing a constant water repellency after corrosion and organic solvents tests, strong resistance under UV light, and thermal stability up to 400 °C. Sandpaper mechanical robustness durability test showed superhydrophobicity for up to 5 rubbing cycles. In this study, a novel strategy to achieve highly transparent superhydrophobic glass surfaces using AACVD of alkoxysilanes, to produce surfaces with excellent durability is described. This shows great potential to obtain silica superhydrophobic films for large-scale applications.