Antifouling PVDF membrane grafted with zwitterionic poly(lysine methacrylamide) brushes

Antifouling PVDF membranes were fabricated through the covalent binding of lysine methacrylamide (LysAA) brushes on the membrane surface via mussel-inspired surface-initiated atom transfer radical polymerization (SI-ATRP). The zwitterionic pLysAA brushes were immobilized on the membrane surface as well as the inner pore surface, which was conducive to enhance the hydrophilicity and separation properties of PVDF membranes due to the strong hydration capacity of zwitterions and amide groups in the brushes. Upon modification, the wetting and antifouling properties of the graft membranes were improved significantly with the water contact angle reduced to as low as 37 degrees and the water flux recovery ratio increased to as high as 95%. This work provides an effective alternative to the traditional poly(ethylene glycol) or poly(betaine)-based materials for the fabrication of low-fouling membranes, which may find its application in blood purification, protein separation and water treatment.