Eco-friendly waterborne superhydrophobic/superoleophilic FEVE composite coating with prolonged mechanochemical and anti-scaling properties

Superhydrophobic surfaces are commonly used for anti-corrosion and anti-scaling of metals and alloys, but their roughness structures are susceptible to damage by the lost superhydrophobicity, limiting their practical applications. In this study, an eco-friendly waterborne superhydrophobic/superoleophilic composite coating was successfully prepared by combining of fluoroethylene vinyl ether (FEVE), polyvinylidene fluoride (PVDF), hydroxylated carbon nanotubes (H-CNTs), and titanium dioxide whiskers (W-TiO2). During the curing process, a network structure composed of W-TiO2 and H-CNTs was evenly distributed on the coating surface to construct uniform micro/nanostructures; these captured a stable air film to prevent the permeation of aggressive ions in water. Simultaneously, the intrinsic photoactivity of the W-TiO2 and the strong CF bonds of PVDF on the prepared coating provided excellent UV resistance and chemical stability. Due to the interfacial enhancement of the network structures and FEVE, the prepared coating showed excellent adhesion ability and mechanical durability; its superhydrophobicity was retained after 600 abrasion cycles under a pressure of 125 kPa. Additionally, the coating demonstrated excellent anti-corrosion and anti-scaling properties in high salinity oil/water emulsions owing to the synergistic effect of the oleophilicity of the non-perfluorinated compounds and absorption of the network structures, which can transform the fragile gas film into a stable oil film to impede scaling and corrosion media. Furthermore, the as-prepared composite coating exhibited excellent self-cleaning and anti-fouling properties against dust and mucus. Therefore, this eco-friendly waterborne superhydrophobic/superoleophilic coating with extraordinary mechanochemical and anti-scaling properties is of great significance for potential applications in harsh environments.