Fabrication of a scratch & heat resistant superhydrophobic SiO₂ surface with self-cleaning and semi-transparent performance

Herein, we report the fabrication of a superhydrophobic surface with a new and effective silica nanocomposite. A facile synthesis was developed by spraying the as-prepared silica suspension on a glass substrate, where the SiO₂ nanoparticles were composed of methylated aerogel particles wrapped by hydroxyl-terminated polydimethylsiloxane (PDMS). Three types of methylated silica aerogel nanoparticles with different surface roughness and porosities were prepared using specific precursors and methylation agents. The coating of the silica aerogels (sodium silicate and trimethylchlorosilane) wrapped in PDMS was exceptionally superhydrophobic with a superior water contact angle of 169.80 ± 3° and a sliding angle of less than 4°. The semi-transparent coating maintained its excellent water repellency at 350 °C for least 4 h and exhibited durable superhydrophobic properties for 6 months at ambient conditions. Additionally, the coating also showed good mechanical stability and remarkable self-cleaning behaviour.