Silica-methyltrimethoxysilane based hydrophobic coatings on a glass substrate

The preparation of silica-methyltrimethoxysilane nanocomposites and their effect on the glass surface wettability performance were investigated. TEOS, sodium silicate, and rice husk ash were the silica sources used. In this research, rice husk ash was converted into sodium silicate through a reaction with amorphous silica and NaOH. The optimum silica concentration providing the highest hydrophobicity was determined. The silica nanoparticles were characterized by XRD, the hydrophobicity was measured by the water contact angle (WCA) test, the surface roughness was analyzed by AFM, while the transparency was determined spectrophotometrically. The different silica source used affected the hydrophobicity of the coated glass. The nanocomposite using TEOS as a silica source showed the highest WCA (132°), whereas sodium silicate and rice husk ash showed similar WCA (around 116°). Furthermore, WCA was also found affected by the amount of silica. WCA increases with silica amount increase.