Stimuli-Responsive Multifunctional Membranes of Controllable Morphology from Poly(vinylidene fluoride)-graft-Poly[2-(N,N-dimethylamino)ethyl methacrylate] Prepared via Atom Transfer Radical Polymerization

Poly(vinylidene fluoride) (PVDF) with poly [2-(N,N-dimethylamino) ethyl methacrylate] (PDMAEMA) side chains were synthesized via vinylidene fluoride-initiated atom transfer radical polymerization (ATRP) of 2-(N,N-dimethylamino) ethyl methacrylate (DMAEMA). The graft copolymer can be readily cast into porous pH- and thermo-responsive microfiltration (MF) membranes with enriched living PDMAEMA graft chains on the surface (including the pore surfaces) by phase inversion in an aqueous medium. The morphology and surface composition of the membranes were characterized by scanning electron microscopy and X-ray photoelectron spectroscopy, respectively. The pH and temperature of the aqueous media for phase inversion and the PDMAEMA content in the PVDF-g-PDMAEMA copolymers can be used to adjust the pore size of the membranes. In addition to having pH and temperature-responsive permeability, the PVDF-g-PDMAEMA MF membranes also exhibit both good antifouling and antibacterial properties, making the membrane potentially useful for biorelated applications. Furthermore, the dormant PDMAEMA chain ends on the PVDF-g-PDMAEMA membrane can be reactivated for the consecutive surface-initiated ATRP of other functional monomers, such as 2-naphthyl methacrylate (2NM), to produce fluorescent PDMAEMA-b-P2NM diblock copolymer brushes on the PVDF membrane.