Structures and antifouling properties of polyvinyl chloride/poly(methyl methacrylate)-graft-poly(ethylene glycol) blend membranes formed in different coagulation media

Two new amphiphilic copolymers poly(methyl methacrylate-graft-poly(ethylene glycol) methacrylate) (PMMA-g-PEG) are synthesized and blended into polyvinyl chloride (PVC) to prepare membranes in different coagulation media (water and ethanol) via the non-solvent induced phase separation method. The prepared membranes are characterized by X-ray photoelectron spectroscopy, proton nuclear magnetic resonance, scanning electron microscopy, atomic force microscopy and water contact angle measurement. Their separation performance and fouling resistance (by protein adsorption and foulant filtration) are also compared. It is found that the membrane hydrophilicity is significantly increased by blending amphiphilic copolymer due to the introduction of hydrophilic poly(ethylene glycol) (PEG) segments of the copolymer. The membranes formed in water have more desirable structures (i.e., smoother surfaces and higher porosity) and better performance (i.e., higher permeability and rejection to bovine serum albumin) compared with those formed in ethanol. The amphiphilic copolymer blended membranes formed in the water coagulation bath exhibit excellent antifouling properties, in particular, showing ~100% fouling reversibility. Therefore, blending amphiphilic copolymers and selecting water as the coagulation media can be effective strategies to develop high performance antifouling membranes.