Green and robust superhydrophilic electrospun stereocomplex polylactide membranes: Multifunctional oil/water separation and self-cleaning

Superhydrophilic materials have attracted extensive attention as promising candidates for effective oil/water separation and water purification, however, realizing environmentally friendly and multifunctional materials with superhydrophilicity and underwater superoleophobicity is still a great challenge and urgently desired. In this work, we develop a controllable approach to achieve the superhydrophilicity of biodegradable electrospun stereocomplex polylactide (sc-PLA) membranes via the titanium carboxylate coordination bonding of gallic acid (GA) and tetrabutyl titanate (Ti(OBu)4) in aqueous solution, i.e. GA-modified TiO2 (GA-TiO2) coating. The GA-TiO2 coated sc-PLA (GT-sc) membranes show superhydrophilicity and underwater superoleophobicity in various harsh working conditions including corrosive organic solvents, saturated NaCl solution and acid solution at pH = 1, exhibiting effective and efficient separation property for a wide range of oil/water mixtures and oil-in-water emulsions. The GT-sc membranes can remove water-soluble contaminants such as methylene blue driven by gravity, leading to multifunctional water purification. Moreover, the GT-sc membranes possess splendid antifouling and self-cleaning performance resulting from the photocatalytic property of TiO2 under UV irradiation. Thus, this work provides an easily controlled route for fabricating green and durable membranes for multifunctional oil/water separation. [Display omitted] •Superhydrophilic biodegradable membrane has been fabricated via a green gallic acid-modified TiO2 coating.•The membranes exhibit multifunctional oil/water separation with high separation efficiency under gravity driven.•The membranes possess outstanding chemical and mechanical stability in various harsh working conditions.•The membranes show excellent anti-fouling and self-cleaning performance.