Superhydrophobic Coating Based on Nano-Silica Modification for Antifog Application of Partition Glass

In this study, vinyl triethoxysilane (VTES), KH-560 and trimethylchlorosilane (TMCS) were used to modify the surface groups of commercially available nano-silica (SiO2, 50 nm), and ethylene vinyl acetate copolymer (EVA) was used as a film-forming agent. EVA/SiO2, EVA/V-SiO2, EVA/K-SiO2 and EVA/T-SiO2 coatings were prepared, respectively. The coatings were characterized by SEM, FTIR, TG and contact angle. It was found that when the mass percentage of SiO2 was 66 wt%, the hydrophobicity performance of the coating could be significantly improved by silica modification. Compared to the EVA/SiO2, the water contact angle (WCA) of the EVA/V-SiO2, EVA/K-SiO2 and EVA/T-SiO2 were increased by 24.0%, 14.4% and 24.6%, respectively. The FTIR results indicated that VTES, KH-560 and TMCS could effectively replace the -OH groups on the surface of the SiO2 after hydrolysis, resulting in the presence of water transport groups on the SiO2 surface. The TG results certified that TMCS had the highest substitution rate (24.6%) for the -OH groups on the SiO2 surface after the hydrolysis. Additionally, the SEM results indicated that T-SiO2 was more easily dispersed in the EVA film-forming agent, leading to a uniform micro-nano surface rough structure, which aligned with the Cassie-Wenzel model. The durability test had demonstrated that the EVA/T-SiO2 maintained its hydrophobic properties even after enduring 40,000 drops of water and the impact of 200 g of sand. Furthermore, it exhibited excellent resistance to acid corrosion, along with superior self-cleaning properties and an anti-fog performance. It also provided outstanding protection against high temperatures and UV radiation for outdoor applications.