Reversible Cross-Linking of Aliphatic Polyamides Bearing Thermo- and Photoresponsive Cinnamoyl Moieties

Photosensitive polymers have gained strong attention in development of different polymeric systems for diverse applications. Particular attention is paid to polymers with cinnamoyl groups either in polymer backbone or in pendent position owing to their excellent photoreactivity and thermoreactivity upon UV light irradiation or heating. This work aims at synthesizing a novel photo- and thermosensitive aliphatic polyamide by anionic ring-opening copolymerization of epsilon-caprolactam and a-cinnamoylamido-epsilon-caprolactam. The photochemical reversible cross-linking of solutions and thermal cross-linking of spin-coated films made up of these new cinnamoyl-functionalized polyamides were monitored by UV-vis spectroscopy. These aliphatic polyamide copolymers were characterized by magic angle spinning solid-state NMR, and their thermal behaviors were studied by thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis.