Polyimide films with antibacterial surfaces from surface-initiated atom-transfer radical polymerization

BACKGROUND: Materials with antibacterial surface properties have attracted extensive scientific interest for research and development in the battle against microbial contamination. The application of antimicrobial polymers minimizes environmental problems and enhances the efficiency, selectivity and lifetime of the antimicrobial agents. In this paper polyimide (PI) films are chosen as the polymeric substrate to be modified due to the good thermal, mechanical and physicochemical properties of PI. The method of preparing PI films with antibacterial surfaces using surface-initiated atom-transfer radical polymerization (ATRP) is described. RESULTS: The results from X-ray photoelectron spectroscopy showed that the surfaces at each stage were modified successfully. The pyridinium groups introduced on the PI surface possessed antibacterial properties and the bactericidal effect of the functionalized PI films on Escherichia coli was evaluated. Quaternization of the pyridine rings of the poly(4-vinylpyridine) (P4VP) brushes gave rise to a high concentration of quaternary pyridinium groups on the PI film surfaces. The antibacterial efficiency of the modified PI film was dependent on the amount of quaternary pyridinium groups on the surface. CONCLUSION: In this research, functional polymer brushes of P4VP were prepared via surface-initiated ATRP from PI films, followed by alkylation of the grafted P4VP with hexyl bromide. The surface functionalization method described has the advantage of being effective in conferring antibacterial properties on polymeric materials. (C) 2008 Society of Chemical Industry