Photopolymerization of Coumarin-Containing Reversible Photoresponsive Materials Based on Wavelength Selectivity

The photoresponse of the coumarin derivative based on reversible photodimerization and photocleavage has been studied for a long time. This paper reports a novel approach of preparing photoresponsive polymer materials containing coumarin structure by photopolymerization based on the wavelength selectivity. A photopolymerizable and photoresponsive monomer, 7-(hydroxyethoxy)-4-methyl-coumarin (AECM), was synthesized, and photopolymerization was performed on it using UV light irradiation (λ = 405 nm). After polymerization the polymer with coumarin pendant groups can achieve reversible photo-induced [2 + 2] dimerization under UV light (λ > 300 nm) and photocleavage of the cross-link to recovery back to the original structure through further irradiation with UV light (λ = 254 nm). What's more, this monomer could be used to produce a high-resolution pattern and photo-responsive pressure sensitive adhesive through photopolymerization. The demonstrated approach opens new perspectives for the design of photoresponse materials.