Antimicrobial membrane surfaces via efficient polyethyleneimine immobilization and cationization

Biofouling control is a major task in membrane separation processes for water treatment and biomedical applications. In this work, N -alkylated polyethylenimine (PEI) is facilely and efficiently introduced onto the membrane surfaces via the co-deposition of catechol (CCh) and PEI, followed by further grafting of PEIs (600   Da, 70   kDa and 750   kDa) and cationization with methyl iodide (CH 3 I). The physical and chemical properties of the constructed membrane surfaces are characterized with scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, zeta potential and water contact angle measurements. Antibacterial assay reveals that the optimized membrane surfaces possess around 95% antibacterial efficiency against Gram-positive Staphylococcus aureus ( S. aureus ) with weak adhesion of bacteria cells after 24   h of bacterial contact. Additionally, the membrane surfaces also exhibit much enhanced antifouling property during the filtration of opposite charged bovine serum albumin (BSA). These results demonstrate a useful strategy for the surface modification of separation membranes by a kind of antimicrobial and antifouling coating.