A transparent superhydrophobic coating with mechanochemical robustness for anti-icing, photocatalysis and self-cleaning

Transparent and conformal superhydrophobic coating with mechanochemical robustness is of great importance for various applications, such as waterproof, self-cleaning, and anti-icing for windows of cars and buildings. However, it remains a daunting challenge to endow the functional surface with programmable wettability. Herein, we propose a hierarchical coating consisting of polydimethylsiloxane (PDMS) nanoparticles (NPs) and PDMS microparticles (MPs) functional NPs through a combination of thermal treatment and spray treatment. The evaporation of PDMS under heat treatment is firstly applied to form a uniform nanoarchitectures, followed by spraying a mixed P25-PDMS dispersion to construct a protective coating with enhanced surface roughness. This resulted coating is conformal and possess reversible wettability on various substrates. In virtue of the light-response property of P25, the reversible wettability between superhydrophobicity and hydrophobicity can be achieved by repetitive UV-light irradiation and dark environment storage. Besides, the coating can maintain superhydrophobicity with high transmittance (76% optical transmittance) after immersion in acid/base solution for 24 h and continuously sand impingement. Furthermore, the coating exhibits mechanochemical robustness against high speed water jet and Elcometer 99 tape peeling test for 30 cycles due to the high adhesion between the robust coating and the glass. For practical application, the coating was demonstrated to have excellent performance in anti-icing, photocatalytic degradation of pollutants and self-cleaning.