Synthesis of Well-Defined Amphiphilic Star-Block and Miktoarm Star Copolyethers via t-Bu-P4-Catalyzed Ring-Opening Polymerization of Glycidyl Ethers

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• 作者：Yusuke Satoh ; Kana Miyachi ; Hirohiko Matsuno ; Takuya Isono ; Kenji Tajima ; Toyoji Kakuchi ; Toshifumi Satoh
• 刊名：Macromolecules
• 出版年：2016
• 出版时间：January 26, 2016
• 年：2016
• 卷：49
• 期：2
• 页码：499-509
• 全文大小：769K
• ISSN：1520-5835

文摘

A comprehensive set of amphiphilic star-shaped block copolyethers with a fixed molecular weight and composition was synthesized via the t-Bu-P₄-catalyzed ring-opening polymerization (ROP) of 2-(2-(2-methoxyethoxy)ethoxy)ethyl glycidyl ether as a hydrophilic monomer and decyl glycidyl ether as a hydrophobic monomer. The three- and four-armed star-block copolyethers, i.e., the (AB)₃-, (BA)₃-, (AB)₄-, and (BA)₄-type star-block copolyethers, where A and B represent hydrophilic and hydrophobic blocks, respectively, were synthesized by the sequential t-Bu-P₄-catalyzed block copolymerization using tri- and tetra-alcohol initiators, respectively, according to the core-first method. The homogeneous growth of each arm was confirmed by cleaving the linkages between the initiator residue and polyether arms. The synthesis of the A₂B₂-, AB₂-, and A₂B-type miktoarm star copolyethers was achieved by the combination of the t-Bu-P₄-catalyzed ROP and azido-alkyne click chemistry. The azido- and ethynyl-functionalized precursor polyethers with the predicted molecular weights were separately prepared by the t-Bu-P₄-catalyzed ROP with the aid of functional initiators as well as a terminator. The intermolecular click reaction of the precursors provided the desired miktoarm star copolyethers. All the obtained star-shaped block copolyethers had a comparable monomer composition (degree of polymerization = 50:50) and total molecular weight (ca. 22?200 g mol^–1) with a narrow dispersity (<1.05). The hydrodynamic diameter and the cloud point analyses for the aqueous micellar solution of the amphiphilic star-shaped block copolyethers revealed that the self-assembly properties were affected by the block arrangements and branched architectures of the amphiphilic polymers.