Polyethersulfone microfiltration membrane modified by an amphiphilic dithiolane-containing copolymer for improving anti-protein-fouling performance and rejection of nanoparticles

To endow polyethersulfone (PES) membranes with enhanced hydrophilicity and anti-protein adsorption performance, amphiphilic dithiolane-containing copolymers poly[poly(ethyleneglycol)methylethermethacrylate-co-2-(methacryloyloxy)ethyl 5-(1,2-dithiolan-3-yl)pentanoate-co-(4-formylphenyl)-2-methylprop-2-enoate]{abbr. Poly(MAPEG-co-MALA-co-MAHA)} with different polymerization degree were successfully synthesized, and then blended with PES to prepare microfiltration membranes by immersion precipitation phase inversion process. The chemical structure and molecular weight of poly(MAPEG-co-MALA-co-MAHA) were characterized by NMR, FTIR and GPC. The morphology and surface property of the as-prepared blending membranes were also characterized by SEM, AFM and contact angle testing etc. Compared with pure PES membrane, the contact angle of PES/poly(MAPEG-co-MALA-co-MAHA) membranes decreased from 74.2 degrees to 53.7 degrees, and the bovine serum albumin (BSA) adsorption declined from 121.4 to 58.8 mu g cm(-2). Meantime, the water flux of PES/poly(MAPEG-co-MALA-co-MAHA) membranes increased from 38.6 to 89.1 L m(-2)h(-1), the flux recovery ratio increased from 68.3% to 93.3% and the irreversible flux decline ratio decreased from 31.7% to 6.7%. Furthermore, the mechanical property of PES/poly(MAPEG-co-MALA-co-MAHA) membrane was better than that of pure PES membrane. In addition, the rejection of BSA and Au nanoparticle reached 77.3% and 66.2% respectively. The results showed that the addition of poly(MAPEG(18)-co-MALA(18)-co-MAHA(18)) with tiny amount could not only improve the hydrophilicity and antifouling of the membrane, but also endow the microfiltration membrane with the rejection of nanoparticles.