Abstract PSf-b-PEG block copolymers with different PEG contents were synthesized to fabricate the highly perm-selective and anti-fouling ultrafiltration (UF) membranes. PEG homopolymer was also blended into the polysulfone casting solutions to fabricate the control (PSf/PEG blend) membranes. The membrane pore structure, surface properties and separation performances of PSf-b-PEG block copolymer membranes and PSf/PEG blend membranes were investigated to identify the role of PEG block for the pore formation. Our results find that the higher PEG content in the PSf-b-PEG block copolymer and in the PSf/PEG blend system was favorable to form more pores and thinner top skin layer with the slightly larger pore size and the higher MWCO of the fabricated membranes. But under the same content, PEG in the block copolymer could help to generate more pores but with similar pore size than PEG in the blend system during the phase-inversion process, which is because of the micro-phase separation of PSf block and PEG block. The fabricated PSf-b-PEG21 (PSf-b-PEG having 21 wt% PEG) membrane had a high water permeation coefficient of 980.0 ± 33.0 LMH/bar and a high BSA rejection above 98%, succeeding the current perm-selectivity upper-bound of the reported polymeric UF membranes. Antifouling experiments confirmed that the PSf-b-PEG21 membrane exhibited a slow and less flux decline during the fouling stage, but a fast and high flux recovery after the backwash cleaning. Our work provides some insights on the relationship of PSf-b-PEG block copolymer composition and membrane structure-separation properties.

中文翻译：

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通过PSf-b-PEG嵌段共聚物的微相分离提高超滤膜的渗透选择性和防污性能

摘要 合成了具有不同PEG含量的PSf-b-PEG嵌段共聚物，以制备高渗透选择性和防污超滤（UF）膜。PEG 均聚物也混合到聚砜浇铸溶液中以制造对照（PSf/PEG 混合物）膜。研究了 PSf-b-PEG 嵌段共聚物膜和 PSf/PEG 共混膜的膜孔结构、表面性质和分离性能，以确定 PEG 嵌段在孔形成中的作用。我们的结果发现，PSf-b-PEG 嵌段共聚物和 PSf/PEG 共混体系中较高的 PEG 含量有利于形成更多的孔和更薄的表皮层，制备的膜具有稍大的孔径和更高的 MWCO . 但在同样的内容下，在相转化过程中，嵌段共聚物中的 PEG 有助于产生更多的孔，但孔径与共混体系中的 PEG 相似，这是因为 PSf 嵌段和 PEG 嵌段的微相分离。制造的 PSf-b-PEG21（具有 21 wt% PEG 的 PSf-b-PEG）膜具有 980.0 ± 33.0 LMH/bar 的高水渗透系数和高于 98% 的高 BSA 截留率，继承了当前的渗透选择性上限报道的聚合物超滤膜的结合。防污实验证实，PSf-b-PEG21 膜在结垢阶段表现出缓慢且较小的通量下降，但在反冲洗后具有快速且高通量的恢复。我们的工作为 PSf-b-PEG 嵌段共聚物组成与膜结构分离特性的关系提供了一些见解。