Superhydrophobic modification of an Al2O3 microfiltration membrane with TiO2 coating and PFDS grafting

Abstract

A novel superhydrophobic Al₂O₃ microfiltration membrane was prepared by the layer-by-layer assembly of TiO₂ coating with subsequent fluorination grafting surface treatment by 1H,1H,2H,2H-perfluorodecyltriethoxysilane. The influence of surface morphology on membrane superhydrophobicity, pore size diameter distributions and pure water permeability of the different membranes were studied. By optimizing the grafting parameters, a needle-like surface of grafted TiO₂-coated Al₂O₃ membrane with a water contact angle of 169.5° was obtained. The pure water permeability of different membranes varied from 100 l m⁻² h⁻¹ bar⁻¹ before grafting to 3–5 l m⁻² h⁻¹ bar⁻¹ after grafting, and the grafted superhydrophobic membrane showed excellent water repellence. The novel superhydrophobic membrane is shown to be promising for liquid–liquid and gas–liquid separation.