Creation of active-passive integrated mechanisms on membrane surfaces for superior antifouling and antibacterial properties

Antifouling mechanisms are critical to membrane structure-property relationship. Currently, most researches focus on either passive fouling-resistant, fouling-release mechanisms or active antibacterial mechanism, the integration of active and passive antifouling mechanisms is much less explored. In this study, a novel modifier bearing three functional segments was designed and utilized for antifouling and antibacterial membrane surface construction. In detail, a block-like copolymer comprising low surface energy poly(hexafluorobutyl methacrylate) (PHFBM), hydrophilic poly(poly(ethylene glycol) methyl ether methacrylate) (PEGMA) and antibacterial poly[2-(methacryloyoxy)ethyl trimethylammonium chloride] (PMTAC) quaternary ammonium salt segments was prepared via free radical polymerization. The copolymer was employed for fabricating PVDF membranes by non-solvent induced phase separation method. The surface enrichment of copolymer was confirmed by XPS analysis. The PHFBM and PEGMA segments created passive fouling-release, fouling-resistant mechanisms whereas the PMTAC segments created active antibacterial mechanism on PVDF membrane surfaces. When utilized for oil/water emulsion filtration, the total flux decline ratio of PVDF/PHFBM-PEGMA-PMTAC membrane was as low as 6.3% and the flux recovery ratio reached nearly 100%. Besides, the antibacterial activity against E. coli and S. aureus was higher than 99%. Hopefully, the strategy of active-passive integrated mechanisms in this study can be applicable to construct diverse antifouling surfaces for water treatment related applications.