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Amphiphilic seven-arm star triblock copolymers with diverse morphologies in aqueous solution induced by crystallization and pH

Research paper by Rui Sun, Ying Wang, Pengfei Gou, Min Zuo, Xiaodong Li, Weipu Zhu, Zhiquan Shen

Indexed on: 23 Dec '17Published on: 23 Dec '17Published in: Chemical Research in Chinese Universities



Abstract

Well-defined amphiphilic seven-arm star triblock copolymers containing hydrophobic crystalline poly(ε-caprolactone)(PCL) blocks, hydrophobic non-crystalline poly(tert-butyl acrylate)(PtBA) blocks and hydro-philic poly(ethylene glycol)(PEG) blocks were precisely synthesized by a combination of ring-opening polymeriza-tion(ROP), atom transfer radical polymerization(ATRP) and “click” reaction. Such star copolymers could self-assemble into “core-shell-corona” micelles and “multi-layer” vesicles depending on the fraction of each block. Meanwhile, the selective hydrolysis of middle PtBA blocks into the poly(acrylic acid)(PAA) blocks allowed the star block copolymers to further change their morphologies of aqueous aggregates in response to pH values.