AbstractAn ethylene glycol-based hexa-block copolymer with six different temperature-responsive blocks was prepared via a reversible addition-fragmentation chain transfer (RAFT) polymerization. 2-(2-methoxyethoxy)ethyl methacrylate (MEO2MA) and oligo(ethylene glycol) methacrylate (OEGMA) were selected as the ethylene glycol-based monomers. Each block of the hexa-block copolymer has a different OEGMA content and thus exhibits a different lower critical solution temperature (LCST). The structures of the block copolymers are similar to gradient copolymers. The molecular weights of the copolymers increased with the number of blocks (first block (P(MEO2MA)): 2800 g/mol, di-block copolymer: 7400 g/mol, tri-block copolymer: 12,000 g/mol, tetra-block copolymer: 18,500 g/mol, penta-block copolymer: 26,800 g/mol, and hexa-block copolymer: 40,400 g/mol) with relatively narrow molecular weight distributions (1.18–1.42). Each block exhibits a different LCST in aqueous solution owing to their different OEGMA contents. To the best of our knowledge, this is the first report of a block copolymer containing more than four types of temperature-responsive blocks. The temperature-responsive properties of the prepared block copolymers were investigated by UV-vis spectroscopy, micro-differential scanning calorimetry, and scanning electron microscopy.An ethylene glycol-based hexa-block copolymer with six different temperature-responsive blocks was prepared via a reversible addition-fragmentation chain transfer (RAFT) polymerization. 2-(2-Methoxyethoxy)ethyl methacrylate (MEO2MA) and oligo(ethylene glycol) methacrylate (OEGMA) were selected as the ethylene glycol-based monomers. Each block exhibits a different LCST in aqueous solution owing to their different OEGMA contents.

中文翻译：

---

由六种不同温度响应嵌段组成的乙二醇基嵌段共聚物的制备

摘要 通过可逆加成断裂链转移（RAFT）聚合反应制备了具有六个不同温度响应嵌段的乙二醇基六嵌段共聚物。选择甲基丙烯酸2-(2-甲氧基乙氧基)乙酯(MEO2MA)和甲基丙烯酸低聚(乙二醇)(OEGMA)作为乙二醇基单体。六嵌段共聚物的每个嵌段具有不同的 OEGMA 含量，因此表现出不同的下临界溶解温度 (LCST)。嵌段共聚物的结构类似于梯度共聚物。共聚物的分子量随着嵌段数量的增加而增加（第一嵌段（P（MEO2MA））：2800 g/mol，二嵌段共聚物：7400 g/mol，三嵌段共聚物：12,000 g/mol，四嵌段共聚物：18,500 g/mol，五嵌段共聚物：26,800 g/mol，和六嵌段共聚物：40，400 g/mol)，具有相对窄的分子量分布 (1.18–1.42)。由于 OEGMA 含量不同，每个块在水溶液中表现出不同的 LCST。据我们所知，这是含有四种以上温度响应嵌段的嵌段共聚物的第一份报告。通过紫外-可见光谱、微差示扫描量热法和扫描电子显微镜研究了制备的嵌段共聚物的温度响应性能。通过可逆反应制备了具有六个不同温度响应嵌段的乙二醇基六嵌段共聚物。加成断裂链转移 (RAFT) 聚合。选择甲基丙烯酸2-(2-甲氧基乙氧基)乙酯(MEO2MA)和低聚(乙二醇)甲基丙烯酸酯(OEGMA)作为乙二醇基单体。