Light-responsive terpolymers based on polymerizable photoacids

Abstract

We present the synthesis and characterization of amphiphilic terpolymers containing photoacids based on 1-naphthol using reversible addition fragmentation chain transfer radical polymerization (RAFT). The respective poly(methyl methacrylate-co-2-(N,N-dimethylamino)ethyl methacrylate-co-1-naphthol methacrylate/methacrylamide) P[MMA_x-co-DMAEMA_y-co-NMA_z/NMAm_z] terpolymers were prepared starting from 1-naphthol derived monomers tNMA and tNMAm via RAFT polymerization und subsequent deprotection of the hydroxyl groups. The resulting materials were characterized using size exclusion chromatography and UV/Vis absorption spectroscopy, the latter also enabling the determination of pK_a in the ground as well as the excited state of the monomers (NMA and NMAm). Afterwards, nanoprecipitation led to the formation of nanoparticles in aqueous media, which exhibited photo-responsive behavior upon UV-irradiation. Nile Red was encapsulated into the nanoparticles as a model hydrophobic guest molecule and we could demonstrate light-triggered release.