Adsorption of pH-responsive amphiphilic copolymer micelles and gel on membrane surface as an approach for antifouling coating

A new approach for the surface modification of polymer membranes prepared by phase inversion technique for antifouling properties is reported. Direct deposition of poly(2-dimethylaminoethyl methacrylate)-b–poly(methyl methacrylate)-b–poly(2-dimethylaminoethyl methacrylate) (PDMA-b–PMMA-b–PDMA) copolymer micelles (core–shell) and gel formed from mixture of polyvinyl alcohol (PVA) and PDMA-b–PMMA-b–PDMA on the polysulfone (PSf-virgin) ultrafiltration membrane surface successfully provides modified membranes with improved antifouling properties and pH-responsive behaviour during both water and protein filtrations. Successful deposition and adsorption of such type of micelle and gel particles on the membrane surface was assessed by combination of SEM, AFM, contact angle, ATR-IR, and zeta potential measurements. The micelle and gel particles preferentially remained on the membranes surface due to their bigger size than the pores on the skin layer and also due to adsorption on the membrane surface by hydrophobic interaction. The modified membranes exhibited much higher rejection of macromolecules and almost steady trend in flux compared to corresponding virgin membranes during filtration operation. The major advantage of this protocol is that the deposited micelles and gel remained on the membrane surface even after filtration and storage of the membrane in water and the modified membranes retained similar performance. The effect of all the micelles and gel components on the membrane performance has been elucidated.