Non-whitening superhydrophobic coating for heritage protection

Superhydrophobic coatings have shown great potential in heritage protection due to their excellent wetting resistance, yet whitening problems have limited their widespread use. Here, we present a non-whitening superhydrophobic coating of nano-SiO2 and perfluorodecyltrimethoxysilane for cultural heritage protection, prepared with the assistance of an ultrasound probe. Due to the high efficiency of the probe sonication, the nanoparticles almost retain their original size, and a porous micro–nano hierarchical structure on the surface is formed, as a result, a non-whitening superhydrophobic coating was obtained. The coating exhibits a high water contact angle of 154.7° and a low roll-off angle of 1.7°, dynamic wetting properties such as anti-jet impact, anti-adhesion, anti-evaporation pressure of droplets, rolling, bouncing, anti-fouling and self-cleaning, and long-term resistance to heat, 254 nm UV radiation, acid, alkali, and sand impact. This coating is suitable for bronze, iron, pottery, sandstone, ivory, lacquer, and other artifacts, and has the potential to address various water-related diseases.