Fabrication and Properties of Hydrophobically Modified ZnO–SiO2 Nanocomposite with Polysiloxane

Studies on the wettability properties of solid surfaces are very important in any of the scientific and industrial fields. The most common principle for a superhydrophobic self-cleaning surface is the lotus effect induced by surface roughness. In this study, silicate compounds have been used to produce hydrophobic surfaces. In this way, firstly, SiO2–ZnO nanocomposite was produced, and then vinyl trimethoxy silane was used to increase the water contact angle (WCA). The structure and morphology of nanocomposites were investigated by infrared spectroscopy (FT-IR), X-ray diffraction pattern (XRD), scanning electron microscopy (SEM) and energy-dispersion spectrometer (EDS) analyses. The thermal stability of nanocomposite coatings was examined by thermogravimetric analysis (TGA). In order to investigate the wetting properties, the surface roughness was measured using an atomic force microscope (AFM), where the subsurface roughness average was obtained at 37.79 nm. The WCA of the coated surfaces with ZnO–SiO2 and ZnO–SiO2 @Polysiloxane nanocomposites were measured at 69 and 160°, respectively, indicating the surface superhydrophobic properties of ZnO–SiO2 @Polysiloxane nanocomposites. Finally, superhydrophobic properties of nanocomposites were investigated by the Cassie-Baxter model. The value of the f2 parameter in the model was estimated at 0.9556. This means that air occupies about 95.56% of the contact area between the water droplet and nano-coating, which is responsible for the superhydrophobic property of the surface.