A mechanically robust and reversibly wettable benzoxazine/epoxy/mesoporous TiO2 coating for oil/water separation

[Display omitted] •A new mechanically robust coating with reversible surface wettability is designed based on benzoxazine/epoxy/mesoporous TiO2.•Water can be conveniently collected after “oil-removing” process.•Oil-water separation flux is larger than 3000 L/m2 h. Bisphenol A type benzoxazine, alicyclic epoxy resin and mesoporous TiO2 nanoparticles were blended and cured to form a ternary BETmes coating by spray coating process. The surface of BETmes coating can be reversed between hydrophilic and hydrophobic through alternate treatment with UV illumination and heating. The chemical composition of this BETmes coating was quantified, its surface morphology was observed, and the mechanism of reversible surface wettability was clarified. The conversion ratio of TiOC/COH groups was maintained at 1.00:1.00. Additionally, the wear resistance of composite BETmes coatings was evaluated by wear testing. This surface exhibited excellent mechanically robust properties because of hydrophobicity retained after abrasion with SiC sandpaper (240 mesh) for 400 cm at an applied pressure of 2.5 MPa. Thus, a membrane with reversible wettability for oil-water separation was developed with this coating, which conveniently generated water. After over five cycles of reutilization, the separation flux was maintained at higher than 3000 L m−2 h−1, peaking at 3318 L m−2 h−1. In conclusion, mechanically robust coatings with reversible surface wettability, which are prepared based on this system, are feasibly applicable to real environments.