Preparation and Properties of Transparent Superhydrophobic SiO2/Silicone Sealant Composite Coatings

Transparent superhydrophobic SiO2/silicone sealant composite coatings were prepared by spray coating method using hydrophobic nano-SiO2 and neutral silicone structural sealant as main raw materials. The molecular structure, microstructure, wettability and light transmittance of the composite coatings were characterized by FTIR, SEM, contact angle measurement and UV-Vis spectrophotometer. The relationship between the content of nano-SiO2 and the surface microstructure, water contact angle and transparency of the coatings was discussed. The water impact resistance and water stability of the composite coatings were also studied. The results showed that the surface of the SiO2/silicone sealant composite coating displayed a continuous porous network structure, and the aggregated SiO2 nanoparticles were dispersed around the sub-micron silicone sealant as the backbones, forming the micro-nano composite rough structures. When the mass fraction of nano-SiO2 was 2.0%, the maximum water contact angle of 169.8°±0.7° and the average transmittance of 82.9% under visible range from 380 nm to 760 nm were obtained. In addition, when the mass fraction of silicone sealant was 4%, the water contact angle of the composite coating remained above 140° after 5 h water impact and 10 d water immersion, respectively. © 2019, Editorial Office of FINE CHEMICALS. All right reserved.