Surface modification of polymeric films and membranes to achieve antibacterial properties

A surface modification technique was developed to impart antibacterial properties on polymeric films and membranes. Poly(ethylene terephthalate) (PET) films and poly(vinylidene fluoride) (PVDF) membranes were first graft‐copolymerized with 4‐vinylpyridine (4VP) and subsequently quaternized with hexylbromide. Both these substrates can be functionalized with varying amounts of pyridinium groups and these groups possess antibacterial properties as shown by assay using waterborne Escherichia coli . The stability of the antibacterial properties of the N ‐hexyl pyridinium groups on the PET film was investigated and the same efficiency in killing the E. coli on contact was observed for the modified film after a 60 day storage in air. Thus, the present surface modification method offers the advantages of simplicity in processing, good control over the surface concentration of pyridinium groups, long‐term stability as well as wide applicability.