LAUSR

Abstract Block copolymers (BCPs) are excellent candidates for surface modification. However, little attention had been directed to systematically investigate the effect of molecular structure on membranes performance, although BCPs of different compositions were extensively blended to membranes before. As a part of this initiative, amphiphilic di-block copolymer (di-BCP) and tri-block copolymers (tri-BCP) with similar compositions were synthesized and used as additives for polyethersulfone membranes which were prepared through the non-solvent induced phase separation (NIPS). The chemical composition of the prepared membranes at different depths, the overall morphology and hydrophilicity were comprehensively characterized. The fouling resistance and rejections to proteins of varied charges and sizes were also evaluated by using the bovine serum albumin and lysozyme as model molecules. On the basis of the results collected from the above analysis, we found that di-BCPs were superior to tri-BCP in improving the membrane's permselectivity but inferior to increasing membrane's hydrophilicity and fouling resistance. The reason for this observation was ascribed to their different reservations and segregation that depended on molecular structures. Typically, tri-BCP tended to reserve in membranes but di-BCP was easily leaked out during membrane formation. This finding is fundamentally important for the preparation of blend membranes with both higher selectivity and better fouling-resistance.