Liquid crystalline PEDOT derivatives exhibiting reversible anisotropic electrochromism and linearly and circularly polarized dichroism
作者:Yong Soo Jeong、Kazuo Akagi
DOI:10.1039/c0jm04183a
日期:——
The multifunctional poly(3,4-ethylenedioxythiophene) [PEDOT] derivatives that exhibit liquid crystallinity, reversible anisotropic electrochromism, and linearly and circularly polarized dichroism are developed. A series of copolymer-type liquid-crystalline PEDOT (LC PEDOT) derivatives are synthesized and evaluated in terms of optical and electrochromic properties. Two of the polymers are monosubstituted LC PEDOT derivatives with phenylcyclohexyl (PCH) or cyanobiphenyl (CB) mesogenic side chain moieties linked to the main chain via an ester bond. Four are disubstituted polymers bearing PCH or CB side chain moieties linked to the main chain via an ester or an ether bond. All of the polymers showed thermotropically nematic LC (N-LC) phases of an enantiotropic nature. Macroscopically aligned LC PEDOT derivatives were prepared by rubbing the polymer films in their N-LC phases, yielding linearly polarized fluorescence and anisotropic electrochromism. The morphologies of the polymer films reversibly changed between the neutral and oxidized states through electrochemical dedoping and doping procedures. The electrochromism between the neutral and oxidized states occurred in the parallel and perpendicular directions of the aligned polymer film, affording a novel anisotropic electrochromism. The chiral nematic LC (N*-LC) phases were also induced in the polymers by adding chiral binaphthyl derivatives as chiral inducer into the LC PEDOT derivatives. The polymer films with the induced N*-LC phase exhibited circular dichroism, implying the formation of an interchain helically π-stacked structure or intrachain helically twisted structure.
开发了具有液晶性、可逆各向异性电致变色以及线性和圆偏振二色性的多官能聚(3,4-乙烯二氧噻吩)[PEDOT]衍生物。合成了一系列共聚物型液晶PEDOT(LC PEDOT)衍生物,并对其光学和电致变色性能进行了评价。其中两种聚合物是单取代的 LC PEDOT 衍生物,具有通过酯键连接到主链的苯基环己基 (PCH) 或氰基联苯 (CB) 介晶侧链部分。四种是带有通过酯或醚键连接到主链的PCH或CB侧链部分的二取代聚合物。所有聚合物均表现出对映异构体的热致向列液晶(N-LC)相。通过摩擦 N-LC 相中的聚合物薄膜,制备了宏观排列的 LC PEDOT 衍生物,产生线性偏振荧光和各向异性电致变色。通过电化学去掺杂和掺杂过程,聚合物薄膜的形貌在中性态和氧化态之间可逆地变化。中性态和氧化态之间的电致变色发生在取向聚合物薄膜的平行和垂直方向上,提供了一种新颖的各向异性电致变色。通过将手性联萘衍生物作为手性诱导剂添加到 LC PEDOT 衍生物中,也可以在聚合物中诱导手性向列 LC (N*-LC) 相。具有诱导N*-LC相的聚合物薄膜表现出圆二色性,这意味着形成了链间螺旋π堆叠结构或链内螺旋扭曲结构。