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Association behavior of different kind of block chains A and C in A-B-C triblock copolymer, and challenge to control the middle B block to form loop or bridge conformation

A-B-C三嵌段共聚物中不同种类的嵌段链A和C的缔合行为，以及控制中间B嵌段形成环或桥构象的挑战

基本信息

批准号：
11450364
负责人：
NOSE Takuhei
金额：
$ 8.45万
依托单位：
TOKYO INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

Possibility to form comicelles with mixed cores comprising of different kind of block chains A and C in A-B-C triblock copolymers and to control the middle B block chain to take loop or bridge conformation has been studied by light scattering and linear and non-linear viscoelastic measurements. Poly (methyl methacrylate), poly (t-butyl acrylate), and polystyrene was used as each A, B, and C blocks, and 1-butanol was used as selective solvent for B block. Following results have been obtained.1) AB and BC diblock copolymer dilute solution forms micelles at room temperature. Near the critical micelle temperature, a huge aggregation was observed and anomalous micellization phenomenon was suggested.2) Semidilute solution of A-B-A triblock forms thermo-reversible physical gel, and its viscoelastic behavior was Maxwell-type with single relaxation time.3) Dilute solution of A-B-C triblock copolymer forms micelles with PS cores when cooled from 100℃. Further cooling induces that PMMA forms core with the already associated PS chains and the middle PtBuA takes loop conformation.4) Semidilute solution of A-B-C triblock copolymer forms physical gel below 50℃. Steady shear deformation induces re-construction of the network structure by the fraction-change of loop and bridge conformation for B chain. The network structure depends strongly on the process to make the gel.

通过光散射和线性和非线性粘弹性测量，研究了在 A-B-C 三嵌段共聚物中形成由不同种类的嵌段链 A 和 C 组成的混合核以及控制中间 B 嵌段链采取环或桥构象的可能性。使用聚(甲基丙烯酸甲酯)、聚(丙烯酸叔丁酯)和聚苯乙烯作为各A、B和C嵌段，并且使用1-丁醇作为B嵌段的选择性溶剂。得到如下结果：1)AB、BC二嵌段共聚物稀溶液在室温下形成胶束。在临界胶束温度附近，观察到巨大的聚集，提示存在异常胶束化现象。2）A-B-A三嵌段共聚物的半稀溶液形成热可逆物理凝胶，其粘弹性行为为麦克斯韦型，具有单一弛豫时间。3）A-B-C三嵌段共聚物的稀溶液从100℃冷却时形成具有PS核的胶束。进一步冷却导致PMMA与已经缔合的PS链形成核心，中间的PtBuA呈环状构象。4)A-B-C三嵌段共聚物的半稀溶液在50℃以下形成物理凝胶。稳定的剪切变形通过 B 链环和桥构象的分数变化诱导网络结构的重建。网络结构很大程度上取决于凝胶的制造过程。