Surface-modified PSf UF membrane by UV-assisted graft polymerization of capsaicin derivative moiety for fouling and bacterial resistance

• Capsaicin derivative moiety was used to prepare antibacterial PSf membrane.
• UV-assisted graft polymerization of MBHBA on PSf was successfully conducted.
• The graft of MBHBA decreased the membrane hydrophilicity and surface roughness.
• Antifouling property against protein of the modified membrane is improved.
• The modified PSf membrane shows excellent antibacterial property.

In this study, the covalently bonding of N-(3-tert-butyl-2-hydroxy-5-methylbenzyl) acrylamide (MBHBA) onto polysulfone (PSf) ultrafiltration membrane surface was performed via UV-assisted graft polymerization. The membranes were characterized by FTIR-ATR, Contact Angle (CA), SEM, AFM, cross-flow filtration unit, antifouling and antibacterial measurements. Verification of MBHBA that photo-chemically grafted onto the PSf membrane surfaces is confirmed by carbonyl stretching vibration at ∼1665 cm−6. The modified membranes show lower hydrophilicity and surface roughness when compared with the pristine membrane. SEM images suggest that membrane pore size is decreased slightly, which is in accordance with the increase of bovine serum albumin (BSA) rejection rate. Notably, BSA filtration test suggests that the antifouling property of the modified membrane is enhanced, even though there is a decrease in the hydrophilicity of the modified membrane surface. Most importantly, the PSf membrane modified with MBHBA exhibits excellent antibacterial properties against Escherichia coli, which implies that the membrane has a good antibiofouling surface.