Novel ultrafiltration membranes with excellent antifouling properties and chlorine resistance using a poly(vinyl chloride)-based copolymer

Novel antifouling and chlorine-resistant ultrafiltration membranes were successfully fabricated using poly(vinyl chloride-co-acrylonitrile-co-sodium 4-styrenesulfonate) (PVC-PAN-PSS), a novel poly(vinyl chloride)-based copolymer, via a non-solvent induced phase separation (NIPS) method. Quartz crystal microbalance data revealed reduced levels of bovine serum albumin (BSA) adsorption on PVC-PAN-PSS films when compared to those of pure poly(vinyl chloride) and polyacrylonitrile films. The morphologies, chemical compositions, surface roughness and hydrophilicity of the membrane surfaces were characterized by field-emission scanning electron microscope (FE-SEM), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and contact angle goniometer, respectively. The hydrophilicity and antifouling properties of the membranes were clearly shown to increase with increasing level of poly(sodium 4-styrene-sulfonate) (PSS) in the copolymer; the membrane with 2 wt% PSS exhibited the best antifouling properties, namely similar to 99% of flux recovery ratio for humic acid (1.0 g L-1). Furthermore, the pore structures and antifouling properties of the PVC-PAN-PSS ultrafiltration membranes were maintained after soaking in 1000 ppm sodium hypochlorite for 168 h, while common membrane additives such as methacryloyloxyethylphosphorylcholine-co-poly(propylene glycol) methacrylate and Pluronic (R) F-127 were rapidly degraded in this oxidizing environment. PVC-PAN-PSS is expected to be a promising ultrafiltration membrane material with both superior antifouling properties and excellent chlorine resistance.