Construction of antifouling zwitterionic coatings on polypropylene microporous membranes via N-hydroxyphthalimide(NHPI) catalysis

Developing polyolefin microporous membranes with good antifouling ability and high separation efficiency is an important and urgent work. Herein, polypropylene microporous membranes (PP (mm)) containing zwitterionic polymer was prepared by grafting poly (sulfobetaine methacrylate) (PSBMA) onto the membrane via N-hydroxyphthalimide(NHPI) catalysis and activators regenerated by electron transfer atom transfer radical polymerization (ARGET-ATRP) for the first time. The structure, morphology, hydrophilicity and antifouling ability of PP (mm)-g-PSBMA was systematically studied. Water contact angle of the modified membrane could be sharply reduced at a proper grafting degree (GD), and it exhibited extraordinary hydrophilicity. The PP (mm)-g-PSBMA membrane also showed excellent protein antifouling ability and higher water flux compared to that of pristine PP membrane. Flux recovery ratio (FRR) of PP (mm)-g-PSBMA was increased to 93.1 % and relative flux reduction ratio (RFR) was decreased to 25.3%. This work presents a controllable and high efficiency strategy to polyolefin separation membrane for high value products.