Designing the anti-biofouling surface of an ultrafiltration membrane with a novel zwitterionic poly(aryl ether oxadiazole) containing benzimidazole

[Display omitted] •ZB-PAEO was synthesized by low-temperature polycondensation and quaternization.•ZB-PAEO membrane presented excellent hydrophilicity and water permeability.•ZB-PAEO exhibited enhanced anti-fouling performance and performance stability.•ZB-PAEO membrane displayed improved anti-biofouling property. To enhance the anti-fouling performance of ultrafiltration (UF) membrane, a novel zwitterionic poly(aryl ether oxadiazole) containing benzimidazole (ZB-PAEO) was synthesized through a two-step process consisting of low-temperature polycondensation and quaternization, which contains two pairs of zwitterionic groups in one polymerization unit and the anti-bacterial imidazole groups. A series of ZB-PAEO membranes with different ZB-PAEO contents were fabricated by the phase inversion process, and their microstructure and performances were tested and characterized. The introduction of carboxymethyl imidazolium groups enhanced the membrane hydrophilicity, substantially strengthening the anti-fouling property and reducing irreversible fouling. Likewise, ZB-PAEO membranes exhibited outstanding anti-biofouling property due to the strong hydration shell formed by the combination of two pairs of zwitterions in a repeating unit with abundant water molecules and the anti-biofouling resistance of the carboxymethyl imidazolium groups. This zwitterionic modification method can be readily extended to various materials and membrane systems to upgrade the anti-fouling property and water permeability.