Dual-Stimuli-Responsive Block Copolymers Derived from Proline Derivatives
Dual-Stimuli-Responsive Block Copolymers Derived from Proline Derivatives
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DOI：
10.1021/ma900706s
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发表时间：
2009-06
期刊：
影响因子：
5.5
通讯作者：
H. Mori;Ikumi Kato;T. Endo
中科院分区：
文献类型：
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作者：
H. Mori;Ikumi Kato;T. Endo
通过可逆加成-断裂链转移（RAFT）聚合合成了包含基于脯氨酸的链段的新型pH和温度响应性嵌段共聚物。选择聚（N-丙烯酰基-l-脯氨酸甲酯），聚（A-Pro-OMe）作为温度响应性链段，而聚（N-丙烯酰基-l-脯氨酸），聚（A-Pro-OH），用作弱阴离子链段。在合适的条件下，可以很好地控制二硫代氨基甲酸酯封端的聚（A-Pro-OH）向A-Pro-OMe的扩链，得到具有设计链结构和低多分散性的嵌段共聚物。然后在水溶液中研究嵌段共聚物的特征pH和温度响应特性。通过改变pH值、盐浓度和共聚单体组成，可以在18 ° C和55 °C之间调节低临界溶解温度（LCST）。用循环伏安法研究了所得嵌段共聚物在水溶液中的手性光学性质和组装结构。
Novel pH- and thermo-responsive block copolymers comprising proline-based segments were synthesized by reversible addition−fragmentation chain transfer (RAFT) polymerization. Poly(N-acryloyl-l-proline methyl ester), poly(A-Pro-OMe), was selected as a thermo-responsive segment, whereas poly(N-acryloyl-l-proline), poly(A-Pro-OH), was employed as a weak anionic polyelectrolyte. The chain extension from the dithiocarbamate-terminated poly(A-Pro-OH) to A-Pro-OMe could be well controlled under suitable conditions, and it provided block copolymers with as-designed chain structures and low polydispersities. The characteristic pH- and thermo-responsive properties of the block copolymers were then investigated in aqueous solutions. By varying the pH, salt concentration, and comonomer composition, the lower critical solution temperature (LCST) can be tuned between 18 and 55 °C. The chiroptical properties and assembled structures of the resulting block copolymers in aqueous solutions were evaluated by circular dichro...