Robust and transparent superoleophobic coatings from one-step spraying of SiO2@fluoroPOS

Transparent superoleophobic surfaces have attracted a great deal of attention due to their broad applications in daily use. But it has been proven that obtaining transparency and superoleophobicity simultaneously is challenging. Here, we report a one-step spraying method to prepare a robust transparent superoleophobic coating using SiO2@fluorinated polysiloxane, which derived through a sol–gel process of fumed SiO2 with tetraethylorthosilicate and perfluorooctyltrichlorosilane. The obtained coating exhibited high transmittance (above 82.3% for wavelength range 400–800 nm) and outstanding superoleophobicity to low surface tension liquids with the contact angles greater than 150° and sliding angles lower than 10°. The influence of SiO2 concentration and spray layer on the transmittance and superoleophobicity of coatings was also investigated. Results showed proper surface roughness and low surface energy are two main factors accounting for superoleophobicity. And to achieve highly transmittance, surface roughness of coating should be less than one-quarter of visible wavelength. More importantly, the superoleophobic coating demonstrated excellent mechanical and chemical stability, which confirmed through a series of experiments such as thermal treating at 300 °C, repelling corrosive liquid droplets, and high-speed sand impact. We envision our findings have a promising development space due to its simple preparation process and outstanding performance.