Towards high-performance polysulfone membrane: The role of PSF-b-PEG copolymer additive

Abstract

Polysulfone (PSF) membranes were prepared by nonsolvent-induced phase separation (NIPS) method using PSF-b-PEG copolymer as pore formation additive. The effects of copolymer composition, hydrophilic chain length and copolymer dosage on membrane morphologies, permeability, stability and biocompatibility were systematically discussed in order to determine the role of the additive. The results suggest that the copolymer composition and dosage play an important role in pore formation. The increase of PEG content in the copolymer results in larger pore size and narrower pore size distribution. The modified membranes show average surface pore sizes in the range of 11.4–15.2 nm, which increase by 14–52% compared to that of the pristine PSF membrane. With increase of copolymer dosage, the pore size increases first and then decreases. The hydrophilic chain length has no significant influence on the pore size and size distribution. The results of pure water flux and rejection agree with the variation of pore size. With increasing the copolymer dosage, the static adsorption of protein and platelet to the membrane is suppressed and thus the antifouling ability is improved. The PSF-b-PEG copolymer outperforms the common water soluble additive (i.e. PVP) in terms of the better pore forming ability and membrane stability, implying that the PSF-b-PEG copolymer would be an alternative to PVP in membrane preparation.