2024 Volume 37 Issue 4 Pages 439-444
In this report, we investigated the effect of the chemical difference in the monomer sequence of polyacrylate copolymers tethering coumarin moieties in the side chains on the progress of photodimerization reaction in their solutions. Random and block copolymers were synthesized from both n-butyl acrylate and a photoreactive acrylate derivative with a coumarin moiety by atom transfer radical polymerization. Photoirradiation of the solution of random copolymers with ultraviolet (UV) light led to slow photodimerization reaction until 3600 s, followed by the rapid reaction. In the case of the solution of block copolymers, however, the reaction progressed rapidly after UV irradiation until 1800 s, and the reaction progressed slowly from 1800 s to 3600 s, and then the reaction progressed rapidly. These tendencies were also observed for other copolymers regardless of the difference in the molar fraction of coumarin moieties. Because the number average molecular weight of all copolymers was identical, it suggested that the progress of photodimerization reaction is largely dependent on the monomer sequence of polyacrylate copolymers.
