Novel transparent, liquid-repellent smooth surfaces with mechanical durability

A simple fabrication method for a smooth and transparent liquid-repellent film has been presented, and the smooth film was successfully obtained through sol-gel process with (3-Glycidyloxypropyl)-trimethoxysilane (GPTMS) followed by surface treatment of air plasma and fluorination. Combination of hydrolyzing of GPTMS and the surface treatment can form covalently interfacial interaction and further enhance surface robustness of the smooth film. The smooth film displays non-wetting behavior towards water and many organic liquids with very low surface tension, such as n-hexane ( gamma sub(l nu ) = 18.4 mN/m) and petroleum ether ( gamma sub(l nu ) = 17.5 mN/m); meanwhile, optical transmittance of the smooth film is greater than 86% throughout a broad spectrum of ultraviolet and visible wavelengths. Importantly, mechanical durability of the obtained film surface was proved by tests of rubbing, wiping, thumb pressing, and peeling of adhesive tape. More surprisingly, the rubbing process can enhance surface non-wetting property and transparency of the smooth film to a certain extent. In addition, the smooth surfaces can also be easily fabricated on other different metal substrates. The impressive liquid-repellency of the smooth surface is concluded to be governed primarily not by surface topography but rather by distribution of fluorine compound on the surface.