Poly(vinylidene fluoride)\nMembranes with Hyperbranched\nAntifouling and Antibacterial Polymer Brushes

Abstract

Graft copolymers of poly­(vinylidene fluoride) (PVDF)\nwith poly­[2-(<i>N</i>,<i>N</i>-dimethylamino)­ethyl\nmethacrylate] (PDMAEMA)\nside chains (PVDF-<i>g</i>-PDMAEMA copolymers) were synthesized\nvia activators generated by electron transfer for atom transfer radical\npolymerization (AGET-ATRP) of 2-(<i>N</i>,<i>N</i>-dimethylamino)­ethyl methacrylate (DMAEMA) directly from the secondary\nfluorine atoms on the PVDF backbone. Microporous membranes were fabricated\nfrom the PVDF-<i>g</i>-PDMAEMA amphiphilic copolymers by\nphase inversion in an aqueous medium. After quaternization by propargyl\nbromide, the resulting PVDF-<i>g</i>-PQDMAEMA membrane and\npore surfaces bearing pendant propargyl moieties could be further\nfunctionalized via surface-initiated alkyne–azide click reaction\nof azido-terminated hyperbranched polyglycerols (HPG-N₃) to form the PVDF-<i>g</i>-P­[QDMAEMA-<i>click</i>-HPG] membranes. The PVDF-<i>g</i>-P­[QDMAEMA-<i>click</i>-HPG] membranes exhibit good resistance to protein adsorption and\nfouling. Alternatively, alkyne–azide click reaction of azido-terminated\npolyethylenimine (PEI-N₃) on the PVDF-<i>g</i>-PQDMAEMA membranes, followed by quaternization with 1-bromohexane,\nproduce the PVDF-<i>g</i>-P­[QDMAEMA-<i>click</i>-QPEI] membrane which is effective in reducing bacterial growth and\nproliferation under continuous-flow conditions.