Hydrophobic Self-Cleaning Coatings for Sustainable Infrastructure

Abstract

Durable two-layer hydrophobic coatings with photocatalytic properties demonstrated a good decomposition of NOx up to 23 %. The first layer of the coating is based on the application of durable titanium phosphate structures. The hydrophobic properties of the coating with a water contact angle of 114° were achieved by the application of water-based siloxane emulsion on the surface of the first layer. Conducted research has demonstrated that the use of hydrophobic coating in comparison with reference TiO2-phosphate can slightly reduce the efficiency for the decomposition of NOx by 8 %; however, this feature can be considered as an acceptable trade-off between the potential improvement of durability of the coating and photocatalytic performance. The formation of layers with very small, around 100 μm, thickness allows to avoid the formation of cracks observed for thicker coatings and contributes to better adhesion of the coating to the surface of substrate material.