A copolymer derivative of poly(4-vinylpyridine propylsulfobetaine) for the design of thermostable bioinert poly(vinylidene difluoride) microporous membranes by vapor-induced phase separation

•A zwitterionic copolymer containing 4-vinylpyridine propylsulfobetaine is presented.•The copolymer can efficiently trap and retain water under low humidity levels.•Bi-continuous zwitterionic membranes are formed efficiently resisting biofouling.•Stability of the antifouling properties after sterilization is demonstrated.