Direct Photomodification of Polymer Surfaces: Unleashing the Potential of Aryl-Azide Copolymers

ABSTRACT

The possibility to impart surface properties to any polymeric substrate using a fast, reproducible and industrially friendly procedure, without the need for surface pre-treatment, is highly sought after. This is in particular true in the frame of antibacterial surfaces to hinder the threat of biofilm formation. In this study we demonstrate the potential of aryl-azide polymers for photo-functionalization and the importance of the polymer structure for an efficient grafting. The strategy is illustrated with a UV-reactive hydrophilic poly(2-oxazoline) based copolymer, which can be photografted onto any polymer substrate that contains carbon-hydrogen bonds to introduce antifouling properties. Through detailed characterization it is demonstrated that the controlled spatial distribution of the UV-reactive aryl-azide moieties within the poly(2-oxazline) structure, in the form of pseudo gradient copolymers, ensures higher grafting efficacy than other copolymer structures including block copolymers. Furthermore, it is found that the photografting results in a covalently bound layer, which is thermally stable and causes a significant anti-adherence effect and biofilm reduction against E. coli and S. epidermidis strains while remaining non-cytotoxic against mouse fibroblasts.