Poly(vinylidene fluoride) Graft Copolymer Membranes with "Clickable" Surfaces and Their Functionalization

PVDF-g-PPMA copolymers bearing pendant propargyl functionalities were prepared by thermally induced graft copolymerization of propargyl methacrylate (PMA) from the ozone-preactivated poly(vinylidene fluoride) (PVDF) backbones. Microporous membranes were fabricated from the PVDF-g-PPMA comb copolymers by phase inversion in aqueous media. The PVDF-g-PPMA membrane and pore surfaces with pendant propargyl moieties from the PPMA side chains could be further functionalized via the one-step surface-initiated thiol-yne click reaction or alkyne-azide click reaction. The electrolyte-responsive PVDF-g-P[PMA-click-MPS] membranes were prepared via thiol-yne click reaction with 3-mercapto-1-propanesulfonic acid sodium salt (MPS) on the microporous PVDF-g-PPMA membranes. The permeability of aqueous solutions through the PVDF-g-P[PMA-click-MPS] membranes exhibited a dependence on the electrolyte concentration. The PVDF-g-P[PMA-click-beta-CD] membranes were synthesized via the alkyne-azide click reaction of mono (6-azido-6-desoxy)-beta-cyclodextrin (azido-beta-CD) on the PVDF-g-PPMA membranes. The PVDF-g-P[PMA-click-beta-CD-guest-PEO] membranes, from surface inclusion complexation of diadamantyl-poly(ethylene oxide) (AD-PRO) guest polymer with the beta-cyclodextrin (beta-CD) host molecules, exhibited good resistance to protein adsorption and fouling under continuous-flow conditions.