Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Chemistry. 2010 Dec 3;16(45):13465-72. doi: 10.1002/chem.200902440.
Side-chain liquid-crystalline siloxane polymers bearing terthiophene moieties as mesogenic pendant groups have been synthesized. An alkenylterthiophene derivative was treated with poly(hydrogenmethylsiloxane) and poly(dimethylsiloxane-co-hydrogenmethylsiloxane)s in Me(2)SiO/MeHSiO ratios of 1:1 and 7:3, respectively, in the presence of the Karstedt catalyst, to produce pale yellow polymers. The degrees of introduction of the mesogenic unit were 100, 50, and 30%, respectively. The polymers exhibit ordered smectic phases at room temperature. The copolymers with dimethylsiloxane units form smectic phases as a consequence of nanosegregation between the mesogenic units and siloxane backbones with the alkylene spacers. Time-of-flight measurement reveals that the hole mobility exceeds 1×10(-2) cm(2) V(-1) s(-1) in the ordered smectic phase of the copolymer with a degree introduction of the mesogenic units of 50%. This value is comparable to that of the highly ordered mesophases of low-molecular-weight derivatives of phenylnaphthalene and terthiophene. Because of the segregation behavior induced by the flexible backbone, a closer molecular packing structure favorable for fast carrier transport may be formed in the smectic phase of the copolymer in spite of the low density of the mesogenic groups.
侧链液晶硅氧烷聚合物带有作为介晶侧基的三噻吩部分已被合成。烯基三噻吩衍生物在存在 Karstedt 催化剂的情况下，分别在 Me(2)SiO/MeHSiO 摩尔比为 1:1 和 7:3 的条件下，与聚(氢甲基硅氧烷)和聚(二甲基硅氧烷- 氢甲基硅氧烷)反应，生成淡黄色聚合物。介晶单元的引入度分别为 100%、50%和 30%。聚合物在室温下表现出有序的近晶相。含有二甲基硅氧烷单元的共聚物由于介晶单元和硅氧烷主链之间的纳米相分离以及亚烷基间隔基，形成近晶相。飞行时间测量表明，在介晶单元的引入度为 50%的共聚物的有序近晶相中，空穴迁移率超过 1×10(-2)cm(2)V(-1)s(-1)。这个值与苯并萘和三噻吩的低分子量衍生物的高度有序介相相当。由于柔性主链引起的相分离行为，即使介晶基团的密度较低，共聚物的近晶相中也可能形成有利于快速载流子输运的更紧密的分子堆积结构。
