A veil-over-sprout micro-nano PMMA/SiO2 superhydrophobic coating with impressive abrasion, icing, and corrosion resistance

Abstract

Superhydrophobic (SHP) coatings have been reported with many promising applications using various nano-micro structures with surfactants of low surface energies. However, many SHP coatings have poor durability, largely limiting their practical importance. In this study, a durable SHP coating is demonstrated with a novel veil-over-sprout micro-nano structure of silica nano particles (SNP) and poly(methyl methacrylate) (PMMA). This coating displays a large water contact angle (WCA) of 168.0° and a small sliding angle (SA) of less than 1.0°. Excellent abrasion resistance is demonstrated with excellent superhydrophobicity (WCA = 159.0°) after consecutive tests with sandpaper, high-density water flow and fine sand impact. An excellent self-healing function has been achieved with this SHP coating after stored at room temperature, recovering its remarkable superhydrophobicity. Outstanding resistance against ice formation is exhibited with the starting-freezing time at −20 ℃ three times longer than uncoated surface. Strong resistance to acid and base attacks is observed even after a week of immersion in highly acidic and alkaline environments (pH 1.0–14.0), without much degradation of SHP performance. Efficiency of up to 99.9% is demonstrated in corrosion protection in a solution with pH = 10.0 to extend the life of the metal. In addition, remarkable SHP durability is demonstrated after long-term outdoor exposure. Therefore, this work has shown off a promising methods for SHP coatings towards future practical applications.