An efficient way to prepare hydrophobic antireflective SiO2 film by sol–gel method

A single-layer hydrophobic antireflective SiO2 film was prepared by sol–gel method. High transmittance (97%) and large static water contact angle (130.6°) were realized simultaneously through a simple and efficient way. Tetraethoxysilane (TEOS) was used as a precursor to prepare SiO2 sol. A dip-pulling method was used to prepare the thin film. We controlled the film thickness by regulating pulling speed for making the transmittance of the film to reach a peak at about 550 nm. The surface of the film was covered with uniform particles of 20–30 nm and pores of 50–60 nm as shown in the SEM images. 1H, 1H, 2H, 2H-perfluorodecyltrichoxy silane (PFDS) was introduced to replace the hydroxyl (–OH) groups and decrease the surface energy of the film. The appropriate SiO2 particle size and porosity in the film and low surface energy give the hydrophobic antireflective SiO2 film with high transmittance and large static water contact angle.