Membrane fouling has been one of the most important challenges in membrane separation operations. In this study, we report a facile strategy to prepare antifouling polysulfone (PSf) UF membranes by blending amphiphilic zwitterion polysulfone-co-sulfobetaine polysulfone (PSf-co-SBPSf) copolymer. The copolymer chemical structure was characterized by 1HNMR spectroscopy. The PSf/PSf-co-SBPSf blend membranes with various zwitterionic SBPSf segment contents exhibited better surface hydrophilicity and excellent antifouling ability compared to PSf and PSf/PEG membranes. The significant increase of both porosity and water permeance indicates that the PSf-co-SBPSf has a pore-forming effect. The pure water flux and flux recovery ratio of the PSf/PSf-co-SBPSf blend membranes were both remarked to improve 286.43 L/m2h and 92.26%, while bovine serum albumin (BSA) rejection remained at a high level (97.66%). More importantly, the water flux and BSA rejection see minimal variance after heat treatment, indicating excellent thermostability. Overall, the PSf/PSf-co-SBPSf blend membranes achieved a comprehensive performance of sustainable hydrophilic, high permeation flux, and remarkable antifouling ability, thus becoming a promising candidate in high-temperature separation application.

Polysulfone ultrafiltration membranes were prepared with sulfobetaine polyimide (s‐PI) via phase inversion process, during which s‐PI migrated and enriched on the surfaces of membranes/pores due to its hydrophilic nature. Therefore, s‐PI not only enhanced surface hydrophilicity, but also acted as a pore‐forming agent. It was proved that the introduction of s‐PI effectively promoted membrane porosity and antifouling ability. Under optimized conditions, the pure water flux of blend membranes reached 220.58 L m−2 h−1 with a protein rejection ratio of 99.3%, and a flux recovery ratio of 90.86%, indicating the superior antifouling property and filtration performances of zwitterionic polymer blend membranes. Moreover, the blend membrane can stand a temperature of 90°C without degrading its separation performance. Besides excellent thermal stability, the blend membranes exhibited a distinctly advanced mechanical strength due to the addition of rigid s‐PI polymer. Overall, this study provided a facile and scalable method for the preparation of antifouling and thermally stable ultrafiltration membranes.