Synthesis of multifunctional block copolymers and their applications to organic electroluminescent devices with pseudo-layered structures

本项目的目的是合成完整的单体聚合物，用于高效的电致发光器件，其中所使用的聚合物显示出自组装能力来创建假层结构。2004年合成了含氟烷基链的荧光棒部分和含咔唑部分的空穴传输聚甲基丙烯酸甲酯的棒盘式嵌段共聚物。结果表明，共聚物的溶液包覆导致了表面分离膜，其中空气-聚合物界面主要覆盖着低表面张力的氟化棒。2005年，设计了含电荷传输聚合物支链的聚噻吩型接枝共聚物。聚噻吩类化合物在溶液状态下通常是强荧光的，但在薄膜状态下会发生严重的猝灭，这限制了聚噻吩类化合物在电致发光器件中的应用。在接枝聚合物中，高密度的支链阻止了聚噻吩键的聚集，保持了溶液中的构象。采用氧化偶联聚合和原子转移自由基聚合相结合的方法成功地合成了接枝共聚物。正如预期的那样，接枝共聚物的薄膜表现出与溶液一样的荧光性质。以乙苯-TEMPO为引发剂，以含空穴和电子传递基团的苯乙烯衍生物为单体进行活性自由基聚合，得到嵌段共聚物。

The purpose of this project is to synthesize the complete monolithic polymers for efficient electroluminescent devices, where utilized polymers show ability to self-assemble to create pseudo-layered structures. In 2004, rod-coil type block copolymers consisting of fluorescent rod part with fluorinated alkyl chains, and hole transporting polymethacrylate with carbazole moiety were synthesized. It is confirmed that the solution coating of resulting copolymers led to surface segregated films where the air-to-polymer interface was predominately covered with low surface tension fluorinated rods. In 2005, graft copolymers based on polythiophene with charge transporting polymers branches were designed. Polythiophenes are generally highly fluorescent in a solution state, but severe quenching occurs in a film state, which limits the utilization of polythiophene in electroluminescent devices. In graft polymers, high density of branch chain prevents the aggregation of polythiophene backbones, keeping the conformation as in the solution. The graft copolymers were successfully synthesized with a combination of oxidative coupling polymerization and atom tranfer radical polymerization. As expected, the films of graft copolymers showed fluorescent natures like the solution. Living radical polymerization using ethylbenzene-TEMPO as an initiator and styrene derivatives with hole and electron transporting moiety as monomers afforded block copolymers.