Light-responsive terpolymers based on polymerizable photoacids

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)/NMAmz] 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 (pK*(a)) of the monomers (NMA and NMAm). Afterwards, nano-precipitation 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.