Utilization of sodium silica from coal fly ash and trimethylchlorosilane as self-cleaning coating on glass

Abstract

Sodium silica is extracted from coal fly ash generated from the power plant. Furthermore, sodium silica is utilized as silica sol, and then it is added to the coating solution with trimethylchlorosilane (TMCS) as an additive. The coating solution is applied to the glass surface by the deep coating method in order to get a self-cleaning glass. This material is usually used as microfluidic devices for biotechnology or bioprocessing. This study aims to analyze the effect of various volume ratios of silica sol and silane sol from TMCS on the physicochemical characterization of the glass surface. The ratios used between silica sol and silane sol are 1:0, 1:1, 1:2, 1:4, and 1:8. Wettability, hysteresis, morphology, and functional group analysis are conducted on the coated glass. The best concentration ratio is 1:8 that produces a contact angle of 107.53°, contact angle hysteresis of 3.13°, and transparency of 99.04%. Moreover, the glass-coated by silica sol-silane sol has surfactant resistance. When Sodium Dodecyl Sulfate (SDS), at a concentration of 2 times of CMC, is dropped on the glass surface inclined at 10°, the droplet slides without leaving a trace. It can be concluded that the glass coated by sodium silica and TMCS has a self-cleaning characteristic.