Dopamine-triggered one-step codeposition of zwitterionic surfactants for anti-fouling polyethersulfone ultrafiltration membrane modification

We report a facile ultrafiltration (UF) membrane modification strategy to impart anti-fouling properties to a polyethersulfone (PES) membrane via a simple codeposition of polydopamine (PDA) and the zwitterionic surfactant, 3-(N, N-Dimethylmyristylammonio) propane sulfonate (SB3-14). The effect of SB3-14 concentration (from 0.5, 1 to 2 mM) was also studied. The proposed modification notably increased membrane anti-fouling property without compromising membrane transport properties. As demonstrated by dynamic fouling experiments using BSA as a model foulant, the modified membranes presented significantly alleviated flux decline and decreased fouling resistance compared to the pristine membrane. Especially, the membrane modified with low SB3-14 concentration (i.e., 0.5 mM) possessed the optimal antifouling performance compared to those modified with higher concentrations, which may be attributed to reduced efficiency in PDA/SB3-14 aggregates functionalization on membrane surface in the presence of excessive zwitterions. Furthermore, the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) results illustrate that Lewis acid-base (AB) played a dominant role during the fouling construction, and the presence of SB3-14 could tremendously decrease AB energy. This codeposition of PDA and non-polymer zwitterionic surfactant could be applied to prepare anti-fouling PES membranes with low reversible and irreversible fouling, which provides a new scope for post modification of UF membranes.