An easy and effective method to prepare superhydrophobic inorganic/organic thin film and improve mechanical property

An easy and effective method for fabricating a two layer structure of superhydrophobic inorganic/organic thin film with good mechanical property was developed by sol–gel process. The inorganic/organic thin film that is composed of SiO₂ sol and polyvinyl butyral (PVB). The modified-SiO₂ nanoparticles was effectively modified by methoxytrimethysilane and sprayed on an inorganic/organic (SiO₂ + PVB)-coated polycarbonate substrate. The water contact angle of the superhydrophobic inorganic/organic (SiO₂ + PVB) thin film was more than 150° and the average transmittance was 92.7% in the visible wavelength (400–700 nm). According to ISO 2409 standard, the adhesion of the coated film has a quality of rank 1. The hardness was greater than 3H as performed by pencil hardness test. In addition, the superhydrophobic property was maintained after the thin film was treated by pressing wipe paper under a 500 g weight and moving it parallel to the sample. The results demonstrate that the superhydrophobic inorganic/organic (SiO₂ + PVB) thin film has properties of superhydrophobicity, and good mechanical and optical properties.