作者：Xiujuan Huang，Yan Xiao，Meidong Lang *
关键字：ATRP, amphiphilic six-arm copolymers, self-assembly
论文来源：期刊
发表时间：2011年

Well-defined six-arm copolymers, comprised of poly(ε-caprolactone) (PCL) and poly(2-(diethylamino)ethyl methacrylate) (PDEAEMA) as the arm and cyclotriphosphazene as the star core were obtained by the combination of ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP). These amphiphilic star-shaped block copolymers S(PCL-b-PDEAEMA)s were characterized by ¹H NMR spectroscopy, size exclusive chromatography (SEC) and differential scanning calorimetry (DSC). The self-assembly behavior of the copolymer in aqueous solution at different pH values was investigated. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) verified that the copolymers were capable of self-assembling into core-shell micelles with different particle sizes under near neutral and basic conditions. They possessed low critical micelle concentrations (CMCs) in the range of 2 to 10 mg/L determined by fluorescence spectroscopy using pyrene as a probe. In addition, UV-Vis spectrometer measurement showed that the copolymer had rapid transformation with temperature and its lower critical solution temperature (LCST) highly depended on the pH value. These copolymers have potential applications in drug delivery system and gene therapy due to their low CMC and stimuli response.