Characteristics of organic-inorganic hybrid coating films synthesized from colloidal silica-silane sol

Colloidal silica/silane sol solutions were prepared in variation with the amount of silane and reaction time. Such sol solutions were synthesized from colloidal silica/tetramethoxysilane(TMOS)/methyltrimethoxysilane(MTMS). Sol solutions were prepared by sol-gel method through two step reactions. In order to understand their physical and chemical properties, dip coating of sol solutions was performed on the glass substrates. The effects of amount of MTMS and reaction time on the formation of coating films were studied. Coating films became transparent as the reaction time increased. Contact angle of coating films increased with increasing the amount of MTMS. Contact angle of coating films decreased with increasing reaction time. Surface free energy of coating films decreased with increasing the amount of MTMS. Surface roughness of coating films decreased with increasing the amount of MTMS when the reaction time was 6 h. When the reaction time was 24, 48 and 72 h, surface roughness of coating films decreased with increasing the amount of MTMS in the beginning, and then increased when further amount of MTMS was added. Plastic hardness increased with increasing the amount of MTMS. Elastic portion inversely decreased with increasing the amount of MTMS. Coating films were stable until 550A degrees C. Thermal degradation temperature of coating films decreased with increasing the amount of MTMS.