Development of photoresponsive coumarin-modified ethylene-co-vinyl alcohol copolymers with antifouling behavior

Abstract

In this work, the modification of ethylene-co-vinyl alcohol (EVOH) copolymer with a coumarin derivative, 7-(hydroxyethoxy)-4-methyl coumarin (HEOMC), has been performed through the incorporation of different reactive groups, p-nitrophenyl chloroformate, succinic anhydride and phthalic anhydride as different linkers between coumarin and EVOH with the aim to obtain photo-responsive materials with improved protein absorption resistance. After purification, the modification degree was calculated by nuclear magnetic resonance and ultraviolet-visible spectroscopy. The thermal properties revealed the crystallinity loss and higher maximum degradation temperatures when EVOH is modified with coumarin derivative. Copolymers were successfully photo-crosslinked through the photo-responsive behavior of coumarin moieties. The micro-hardness test shown an increase of the mechanical performance due to the coumarin presence. The water contact angle measurements revealed that while coumarin-modified EVOH copolymers present a higher hydrophilic behavior than EVOH, the photo-dimerization process mainly leads to slightly deviations on the surface wettability of neat EVOH. Finally, the absorption of bovine serum albumin onto the surface of the coumarin-modified materials revealed enhanced antifouling properties, particularly after the photo-crosslinked process. Therefore, the introduction of coumarin through different chain extenders leads to functional materials with tunable photo-responsive performance and protein absorption resistance.