A new synthetical process of PVDF derivatives via atom transfer radical graft polymerizations and its application in fabrication of antifouling and antibacterial PVDF ultrafiltration membranes

In this study, poly(vinylidene fluoride)-graft-poly(2-hydroxyethyl methacrylate) (PVDF-g-PHEMA) and poly(vinylidene fluoride)-graft-poly(dimethylamino)ethyl methacrylate) (PVDF-g-PDMAEMA) covalently binding onto the PVDF polymer synthesized by atom transfer radical polymerization (ATRP), were used as additives in the manufacture of novel PVDF ultrafiltration (UF) membranes. The hydroxyl groups on the PVDF-OH polymer by Fenton reaction were used for the immobilization of alkyl halide ATRP initiator. The effects of chemical composition and surface morphology on blend membrane were investigated by X-ray photoelectron spectroscopy, Fourier transform infrared spectrometer, scanning electron microscopy and thermo-gravimetric analysis. Water contact angles and water intake measurements indicated that the introduction of PHEMA graft chains promoted remarkably the surface hydrophilicity of PVDF membranes. It was also found that PVDF/PVDF-g-PHEMA blend membrane provided higher pure water flux of 87.9 l/m(2) h and better anti-protein adsorption ability to PVDF membranes. In filtration studies, blend membranes prepared with PVDF-g-PDMAEMA-g-PHEMA were found to keep the higher pure water flux than the pristine PVDF UF membrane. The PVDF/PVDF-g-PDMAEMA and PVDF/PVDF-g-PDMAEMA-b-PHEMA blend membranes exhibited excellent antibacterial properties against Escherichia coliform reaching more than 80%.