Ultra/loose nano-filtration polyarylene ether sulfone membranes with reversibly tunable pore size enabled via amine oxide units

Developing a new generation of polymer membranes with switchable pores for multiple separation processes remains challenging due to the lack of materials with reversible and adjustable chemical structures . Herein, amine oxide units were introduced in the chains of poly (arylene ether sulfone) via oxidizing the tertiary amine (TA) in poly (arylene ether sulfone)/amide tertiary amine (PAES/ATA) copolymer , and then served as switches to tune the pores of the prepared membranes. The smart membranes could be reversibly tuned between loose nanofiltration mode with water permeance of 178 L m −2  h −1 bar −1 and dye (e.g., Rhodamine B) rejection of 95%, and ultrafiltration mode, with water permeance of 650 L m −2  h −1 bar −1 and dye rejection of 55%, by cyclic acid-alkali treatment. The mechanism of the switchable pore size was elucidated by dissipative particle dynamics (DPD) simulations, and the results were in good agreement with experimental results. This study provides a novel and facile route to fabricate functional membranes with reversibly tunable and highly efficient filtration performance, which could be applicable to multiple separations.