Thin Film Polyamide Membranes with Photoresponsive Antibacterial Activity

Abstract Membranes containing a photosensitizer molecule as part of the selective layer are proposed with demonstrated anti‐biofouling activity. For the membrane preparation, mixtures of an amine‐functionalized photosensitizer molecule, (5,10,15,20‐(tetra‐4‐aminophenyl)porphyrin) and m‐phenylene diamine (MPD) reacted with trimesoyl chloride (TMC) by interfacial polymerization to form thin polyamide films on top of an asymmetric porous support. A highly permeable membrane (35.4 Lm −2 h −1 bar −1 ) with 99 % rejection of Brilliant Blue R (826 g/mol) was obtained using 0.25 wt% porphyrin and 0.75 wt% MPD as amine monomers. Under visible light exposure, singlet oxygen ( 1 O 2 ) is generated in the porphyrin containing‐polyamide film, reaching the bacteria in the feed by diffusion and enhancing the biofouling resistance and anti‐microbial activity. Anti‐biofouling and anti‐microbial photoactivity in solution are demonstrated on Staphylococcus aureus at different porphyrin concentrations and light exposure time.