Surface coating of membrane by cationic photopolymerization of oxetane-terminal poly(ethylene glycol) for enhanced dye/salt separation and chlorine-resistant performance

Cationic photopolymerization is well-known for its tolerance with oxygen and low shrinkage of coating; however, its application for surface coating is limited due to the lack of functional oligomers. Herein, poly (ethylene glycol) (PEG) with terminal oxetane groups was prepared and used for the coating of membrane by rapid cationic photopolymerization. The structure and separation performance of membrane could be regulated by adjusting the molecular weight of PEG and the UV radiation time. The hydrophilicity and filtration performance of membrane has been significantly enhanced after cationic photopolymerization. Finally, the composite membrane showed excellent performance to dye/salt separation and superior chlorine resistance, with flux and retention remaining stable over a 14-day test.