One-step synthesis of a mid-chain functional macrophotoinitiator of a polystyrene-poly(ε-caprolactone) diblock copolymer via simultaneous ATRP and ROP using a dual-functional photoinitiator

Abstract

A one-step synthesis of a well-defined mid-chain functional macrophotoinitiator of a polystyrene-poly(ε-caprolactone) diblock copolymer (PSt-PI-PCL) was successfully performed at 110 °C using a novel dual-functional photoinitiator via simultaneous atom transfer radical polymerization and ring-opening polymerization (ROP). This dual-functional photoinitiator (Br-PI-OH), possessing a bromine group on one end and a hydroxyl group on the other, was synthesized by the reaction of the photoinitiator 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone (HO-PI-OH) with 2-bromopropanoyl bromide. The two distinct polymerization reactions initiated by Br-PI-OH proceeded in a controlled manner without mutual interference. Elemental analysis and 1 H-NMR, 13 C-NMR and Fourier transform infrared spectroscopy (FT-IR) spectroscopy were used to characterize the chemical structure of Br-PI-OH. Characterization of the macrophotoinitiator PSt-PI-PCL was achieved using 1 H-NMR, FT-IR, gel permeation chromatography, UV-vis and fluorescence spectroscopy.