Fabrication of superhydrophobic silica-based surfaces with high transmittance by using tetraethoxysilane precursor and different polymeric species

The preparation of superhydrophobic silica-based surfaces via the sol-gel process through the addition of different polymeric species into the precursor solution was done in this study. The surface roughness of the films was obtained by removing the organic polymer at a high temperature, and then the hydrophobic groups were bonded onto the films with a monolayer by chemical reaction with hexamethyldisilazane (HMDS). The characteristic properties of the as-prepared films were analyzed by contact angle measurements, scanning electron microscopy (SEM), atomic force microscopy (AFM), nitrogen adsorption/desorption, and UV-vis scanning spectrophotometer. The experimental results revealed that the superhydrophobic thin films with high transmittance could easily be prepared using polypropylene (PPG), polyethylene (PEG), and poly(vinylpyrrolidone) (PVP). Surface roughness and pore size were enhanced using PPG polymeric species. The distribution of pore size was from the microporous to the mesoporous and marcoporous regions. In addition, the contact angles of the rough surfaces prepared at 500 °C without modification of HMDS were smaller than 5° but larger than 156° after modified by HMDS.