Preparation of Wear-resistant Hydrophobic SiO₂ Coating by Atomizing Spraying and Application

Hydrophobic silica gel was prepared using methyl trimethoxy-silane (MTMS) as the precursor, while cetyltrimethyl ammonium bromide (CATB) was used to control the degree of polymerization. Then, surface of wood was sprayed by atomizing spray on one side and hydrophobic SiO₂ coating was then obtained after drying at 80 ℃. Surface morphology, chemical composition, surface wettability and wear resistance of the coating were characterized by using field emission scanning electron microscope (SEM), Fourier infrared (FT-IR) spectroscopy, contact angle meter and automatic surface area and porosity analyzer. As compared with those made with the mixed spraying method, the coating prepared by using the sol-gel spraying method has higher wear resistance. When the content of CATB was 15 mmol·L⁻¹, the wear resistance of the coating was optimized. When the content of CATB was 20 mmol·L⁻¹, the hydrophobicity of the coating was the highest, with water contact angle of 148.76±0.94°. The hydrophobicity of the coating was attributed to the presence of CH₃ derived from MTMS, while the enhanced wear resistance was ascribed to the accumulation of the hydrophobic silica gel on surface of the substrate. The hydrophobic silica prepared with MTMS has promising stability and strong acid and alkaline resistance. Based on the 3D uniform porous tubular structure of wood and unilateral atomization spraying technology, double-sided asymmetric wettability film was constructed, which has a wide application prospect in the field of oil/water mixture separation.