Surface modification of PES ultrafiltration membrane by polydopamine coating and poly(ethylene glycol) grafting: Morphology, stability, and anti-fouling

Polydopamine (PD) coating and PD-graft-poly(ethylene glycol) (PD-g-PEG) surface modification can be used to improve the anti-fouling properties of membrane surface. This work studies the features of polyethersulfone (PES) membranes with different molecular weight cut-off (MWCO) modified by PD coating and PD-g-PEG modification on their morphology, stability, and adsorbability. The stability of modified membranes was evaluated by immersion tests. Bovine serum albumin (BSA) was used as a model foulant to investigate the anti-biofouling performance of modified membranes. The results of stability tests showed that both modified membranes had a fine mechanical stability, and the PD-g-PEG modified membrane had a better chemical stability. The images of FESEM and AFM indicate the modifications of PD coating and PD-g-PEG changes the morphology of the PES ultrafiltration (UF) membrane apparently. The modified membranes had less flux reduction in filtration and lower adsorptive amount of BSA in isothermal adsorption tests. The PD-g-PEG modification improves the stability of the PES membrane and the adsorbability for BSA more significantly.