“Clickable” Interfacial Polymerization of Polythioether Ultrathin Membranes for Ion Separation

Ultrathin membranes by interfacial polymerization can efficiently purify high-salinity water, but the variety beyond classic polyamide is limited yet. Based on the modular and rapid feature of click chemistry, this work for the first time reports a "clickable" IP strategy to prepare polythioether ultrathin membranes for ion separation. Multiple sets of multifunctional thiol and alkene/alkyne monomers are proven to react at the water–oil interface via thiol–ene/yne addition polymerization. In particular, triallyl cyanurate-DL-dithiothreitol and triallyl isocyanurate-DL-dithiothreitol ultrathin membranes prepared on polyether sulfone substrates reach the separation accuracy of nanofiltration with rejections to Na2SO4 of over 95%. Their surfaces remain negatively charged in both acidic and alkaline environments, and thioether linkages even stand the challenge of long-term acid treatment with high concentration. This strategy would thus motivate growing attempts at developing new-type ultrathin membranes for ion removal or desalination.