Atom Transfer Radical Polymerization of Glycidyl methacrylate triblock copolymer using a Novel Fluorescence Based Bifunctional Initiator

Abstract

A novel bifunctional initiator containing fluorescein, a fluorescent moiety, was prepared by reacting dihydroxy fluorescein and 2-bromoisobutyl bromide. The structure elucidation of the new initiator was carried out using various spectroscopic tools such as NMR, IR and mass spectrum. Novel, fluorescent triblock copolymers comprising of glycidyl methacrylate namely P(GMA-b-MMA-b-GMA) was successfully synthesized by the atom transfer radical polymerization (ATRP) method using CuBr as the catalyst and N, N, N1, N11, N111 – pentamethyldiethylenetriamine as a complexing agent. The polymers were characterized both by 1H NMR and GPC measurements. It was observed that as the polymerization time increased, both the conversion and the molecular weight increased linearly with time. Well controlled soluble PGMA and triblock copolymers were successfully synthesized by utilizing the controlled radical polymerization method. Fluorescent PGMA was highly fluorescent with distinguishable emission signatures from the fluorescein group and the repeating units of the polymer. The fluorescence emission spectra reveal interesting features such as red shift when compared to the non-fluorescent polymer.