Three well-defined crystalline–coil diblock copolymers of oligo(p-phenylenevinylene)-b-poly(N-isopropylacrylamide) (OPV₅-b-PNIPAM₁₈, OPV₅-b-PNIPAM₄₉, and OPV₅-b-PNIPAM₇₅; the subscripts represent the number of repeat units of each block) with the same crystallizable core-forming OPV segment but different corona-forming PNIPAM blocks of various chain lengths were synthesized. Their solution self-assembly behavior was examined in methanol, ethanol, and isopropanol. Both the solvent and the length of the PNIPAM block were found to affect the self-assembly of the block copolymers. In methanol, OPV₅-b-PNIPAM₁₈ formed a mixture of fiber-like micelles of uniform width and two-dimensional platelet-like structures with fiber-like micelles protruding from the ends. In ethanol and in isopropanol, this polymer only formed long fiber-like micelles of uniform width. OPV₅-b-PNIPAM₄₉ formed long fiber-like micelles (several micrometers) of uniform width in all three solvents, but under the same self-assembly conditions, OPV₅-b-PNIPAM₇₅ only formed short fiber-like micelles with lengths of several hundred nanometers. We systematically examined the temperature-induced self-seeding behavior of all three block copolymers, exploring the influence of PNIPAM chain length, solvent, annealing time, and concentration of copolymer. The most remarkable result of these experiments is our finding that fiber-like micelles of uniform length with controlled lengths up to 1 μm can be easily prepared from all three block copolymers, even from OPV₅-b-PNIPAM₇₅ that formed only much shorter micelles under self-nucleated self-assembly. We also showed that the self-seeding strategy can be extended to other OPV-containing diblock copolymer such as OPV₅-b-poly(2-(diethylamino)ethyl methacrylate) for preparing monodisperse fiber-like micelles of controllable length. These results show that the self-seeding approach to crystallization-driven self-assembly can be a versatile route to prepare uniform fiber-like micelles with controllable lengths for OPV-containing block copolymers.

中文翻译：

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具有π共轭低聚物（对苯撑亚乙烯基）链段的嵌段共聚物的自播：一条通向单分散纤维状纳米结构的多功能途径。

三种定义明确的低聚（对苯撑亚乙烯基）-b-聚（N-异丙基丙烯酰胺）（OPV ₅ - b- PNIPAM ₁₈，OPV ₅ - b- PNIPAM ₄₉和OPV ₅ - b- PNIPAM _75的结晶-线圈二嵌段共聚物; 下标代表每个嵌段的重复单元数），具有相同的可结晶形成核的OPV链段，但合成了不同链长的不同形成电晕的PNIPAM嵌段。在甲醇，乙醇和异丙醇中检查了它们的溶液自组装行为。发现溶剂和PNIPAM嵌段的长度都影响嵌段共聚物的自组装。在甲醇中，OPV ₅ - b- PNIPAM ₁₈形成了均匀宽度的纤维状胶束和二维血小板状结构的混合物，其中二维纤维状胶束从末端突出。在乙醇和异丙醇中，这种聚合物仅形成均匀宽度的长纤维状胶束。OPV ₅ - b -PNIPAM₄₉在所有三种溶剂中形成了均匀宽度的长纤维状胶束（几个微米），但是在相同的自组装条件下，OPV ₅ - b -PNIPAM ₇₅仅形成了长度为几百纳米的短纤维状胶束。我们系统地研究了所有三种嵌段共聚物的温度诱导的自种性，探讨了PNIPAM链长，溶剂，退火时间和共聚物浓度的影响。这些实验最显着的结果是我们发现，即使从OPV ₅ - b -PNIPAM _75上，也可以很容易地从所有三种嵌段共聚物中制备出具有均匀长度且控制长度达1μm的纤维状胶束。在自成核自组装下仅形成短得多的胶束。我们还表明，自种策略可以扩展到其他含OPV的二嵌段共聚物，例如OPV ₅ - b-聚（2-（二乙基氨基）乙基甲基丙烯酸酯），以制备可控制长度的单分散纤维状胶束。这些结果表明，以结晶为驱动力的自组装的自种方法可以成为制备长度可控制的均匀纤维状胶束的通用途径，以制备含OPV的嵌段共聚物。