Improved antifouling property of zwitterionic ultrafiltration membrane composed of acrylonitrile and sulfobetaine copolymer

A random copolymer poly((2-dimethylamino ethyl methacrylate)-acrylonitrile) (PAN–DMAEMA) was synthesized by copolymerization of 2-dimethylamino ethyl methacrylate with acrylonitrile through the water phase suspension polymerization method. The PAN–DMAEMA copolymer was then reacted with 1,3-propane sultone (PS) to convert the DMAEMA group into zwitterionic N,N-dimethyl-N-methacryloxyethyl-N-(3-sulfopropyl) (DMMSA) functional group. The as-prepared PAN-based zwitterionic copolymer was blended with polyacrylonitrile to fabricate ultrafiltration membranes. Ultrafiltration experiments revealed that membrane fouling, especially irreversible membrane fouling, was remarkably reduced due to the incorporation of zwitterionic DMMSA groups. For the PAN-based zwitterionic blend membrane with a DMMSA content of 5.8 mol%, the flux recovery ratio could reach as high as 95% under simple water flushing.