Improve the mechanical durability of superhydrophobic/superamphiphobic coating through multiple cross-linked mesh structure

Abstract

Superhydrophobic/superamphiphobic coatings have attracted extensive attention because of their unique liquid repellency, but their poor durability hinders their large-scale application in the market. This paper designs and synthesizes a mesh structure that uses covalent bonds to link the roughness-building nanoparticles, film-forming polymer, and the substrate together, which significantly improves the stability and durability of the coating. Firstly, the acrylate copolymer (FHA) containing silicon monomer and fluorine monomer was synthesized by free radical polymerization. Then FHA, SiO2/TiO2 nanoparticles, and self-made crosslinker (AG) were connected to form a meshwork structure by Si-O-Si bond through a hydrolysis condensation reaction. Finally, the curing agent (HDI) was added before dip-coating, and the coatings were firmly linked to the substrate through secondary cross-linking. The single-factor experiment showed that when silicon monomer was 12 wt%, fluorine monomer was 5 wt% and FHA content was 16 wt%, the coatings displayed the 5B adhesion. The contact angle (CA) to water, diiodomethane, soybean oil， rapeseed oil, hexadecane, kerosene, waste engine oil on the FAFH-SiO2 coating (consists of the mesh structure and SiO2 nanoparticles) were 158.7° ± 1.5°, 151.1° ± 1.6°, 150.1° ± 1.7°, 150.4° ± 1.5°, 141.1° ± 1.6°, 142.2° ± 1.9°, and 144.7° ± 1.8°, respectively. The coatings could maintain WCA (water contact angle) > 150° after immersion in HCl (PH = 1), toluene, ethanol, and acetone for 84 h. The sandpaper abrasion, water flow scouring, high-pressure steam cooking, machine washing, and environmental exposure tests proved that the coatings have excellent stability and durability. This method for enhancing the durability of the coatings is suitable for particles and substrates containing active hydrogen or hydroxyl groups, which has a wide range of application prospects.