Substitute Effect of Fluorine-containing Polyimides with Hexafluoroisopropylidene Group on Photo Alignment of Liquid Crystal Molecule
Substitute Effect of Fluorine-containing Polyimides with Hexafluoroisopropylidene Group on Photo Alignment of Liquid Crystal Molecule
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六氟异丙叉取代含氟聚酰亚胺对液晶分子光取向的影响
DOI：
10.2494/photopolymer.24.617
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Setsuko Matsumoto
中科院分区：
文献类型：
--
作者：
Shuichi Sato;Hiroto Ito;T. Mizunuma;K. Nagai;H. Matsumoto;Setsuko Matsumoto
系统研究了含氟聚酰亚胺(6FDA)取代基对液晶(LC)分子光取向的影响以及254 nm线偏振紫外光(LPUV)照射对其化学结构的影响。6FDA-2，3，5，6-四甲基-1，4-苯二胺(TeMPD)显示了LC分子的光取向特征。红外和紫外吸收光谱表明，虽然聚合物链段之间发生了光反应，但没有观察到LPUV照射下的光断裂反应。LPUV辐照的6FDA-TeMPD的光取向特性强烈依赖于亚胺环上C=O基团与CH_3基苯基π-π~*跃迁的光反应。通过LPUV辐射机理，分子间聚合物链段之间C=O双键和C-H键的激发以及过氧化氢O-H的形成改变了聚合物的化学结构。然后，给电子的苯环和接受电子的亚胺环在聚合物链的两侧之间形成电荷转移络合物(CTCs)；明显地形成了与两侧交叉的交替顺序的结合。在CTC结构的光反应的一个方向上，6FDA-TeMPD显示了LC分子的光排列。
The substituent effect of fluorine-containing polyimides with 4,4-(hexafluoro-isopropylidene) diphthalic anhydride (6FDA) group on the photo alignment of the liquid crystal (LC) molecule and the effect of 254 nm linearly polarized ultraviolet (LPUV) irradiation on the chemical structure were systematically investigated. 6FDA-2,3,5,6-tetramethyl-1,4-phenylene diamine (TeMPD) showed the photo alignment characteristic of the LC molecule. Based on the infrared and ultraviolet absorption spectra, the photo-scission reaction of LPUV irradiation was not observed, though photoreaction between polymer segments was observed. The photo alignment characteristic of LPUV-irradiated 6FDA-TeMPD strongly depended on the photoreaction between the C=O group of the imide ring and the CH3 group for phenyl-group π-π* transitions. The chemical structure changed with the excitation of C=O double bonds and C-H bonds and the formation of hydroperoxide O-H between the intermolecular polymer segment through the LPUV irradiation mechanism. The electron-donating benzene ring and the electron-accepting imide ring then formed charge transfer complexes (CTCs) between the two sides of polymer chains; the combination with the alternation sequence to both cross sides was clearly formed. In one direction of the photoreaction in the CTC structure, 6FDA-TeMPD showed the photo alignment of the LC molecule.