Multifunctionalization of Poly(vinylidene fluoride)/Reactive Copolymer Blend Membranes for Broad Spectrum Applications.

Simultaneous immobilization and cross-linking of antifouling/low toxic polymers, e.g., poly(ethylenimine) (PEI), dextran (Dex), agarose (Agr), poly(ethylene glycol) (PEG), PEI-Dex, and PEI-PEG conjugates, and stimuli-responsive copolymers on a porous membrane surface in mild reaction conditions is desirable for the enhancement of hydrophilicity, antifouling character, cytocompatibility, and inducing stimuli-responsive behavior. Grafting to technique is required since the precursors of most of these macromolecules are not amenable to surface-initiated polymerization. In this work, we report a versatile process for the simultaneous immobilization and cross-linking of a library of macromolecules on and into the blend membrane (PVDF-blend) of poly(vinylidene fluoride) and poly(methyl methacrylate)-co-poly(chloromethylstyrene). Sequential nucleophilic substitution reaction between activated halide moieties of the copolymer and amine groups of different macromolecules readily provided series of modified membranes. These membranes exhibited antifouling property superior to that of the unmodified membrane. The effectiveness of this technique has been demonstrated by the immobilization of pH or both pH- and temperature-responsive copolymer on PVDF-blend membrane for responsive separation of poly(ethylene oxide) and bovine serum albumin. Silver nanoparticles were also anchored on the select modified membranes surfaces for the enhancement of antibiofouling property. Our approach is useful to obtain verities of functional membranes and selection of membrane for a particular application.