Wetting-induced superlyophobic polyacrylonitrile membranes: From reversible wettability to switchable on-demand emulsion separation

Super-wettable membranes have been extensively investigated due to their prospective applications in oily wastewater remediation. However, it is still a big challenge to develop super-wettable membranes via a facile and rationally designed method. In this work, we proposed a novel strategy to develop wetting-induced superlyophobic polyacrylonitrile (PAN) membranes with reversible wettability via in situ cross-linking polymerization and surface immobilization of nanoparticles during phase inversion process. The resulting membranes exhibited super-amphilic property in air, and were capable of converting their wetting behavior from underwater superoleophobicity to underoil superhydrophobicity with excellent dynamic stability. The membranes also displayed outstanding separation capability toward various surfactant-stabilized emulsions with separation efficiencies exceeding 99.2% under gravity. Moreover, the membranes could be regenerated with high performance preserved using a facile rinsing-and-drying method, and could be repeatedly applied to separate surfactant-stabilized emulsions. This work has made progress in the fabrication of super-amphiphilic membranes with superior separating performance through a facile method, providing great potential in practical application for oily wastewater treatment .