Photoinduced orientation in photoreactive hydrogen-bonding liquid crystalline polymers and liquid crystal alignment on the resultant films
Photoinduced orientation in photoreactive hydrogen-bonding liquid crystalline polymers and liquid crystal alignment on the resultant films
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DOI：
10.1021/ma061381p
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发表时间：
2006-11
期刊：
影响因子：
5.5
通讯作者：
E. Uchida;N. Kawatsuki
中科院分区：
文献类型：
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作者：
E. Uchida;N. Kawatsuki
使用线性偏振紫外（LPUV）光照射探索了侧链上具有以4-羟基肉桂酸封端的六亚甲基间隔基（P6 CAM）的聚甲基丙烯酸酯的光诱导取向。由于肉桂酸基团之间的氢键，P6 CAM表现出液晶相，肉桂酸部分的轴选择性光反应产生的薄膜的光学各向异性。当暴露的膜被退火或原始膜在升高的温度下暴露于LPUV光时，实现了垂直于和平行于LPUV光的偏振（E）的分子重新取向，并且产生的双折射为0.15。用偏振紫外光谱和红外光谱研究了薄膜的取向行为。此外，分子取向通过在升高的温度下退火而被擦除，而再次暴露于LPUV光则重新组织取向。最后，对低分子液晶在聚乙烯基片上的均匀取向控制进行了研究。
The photoinduced orientation in polymethacrylate, which has a hexamethylene spacer group terminated with a 4-oxycinnamic acid in its side chain (P6CAM), is explored using linearly polarized ultraviolet (LPUV) light irradiation. Because of the hydrogen- (H-) bonding among the cinnamic acid groups, P6CAM exhibits a liquid crystalline phase, and the axis-selective photoreaction of the cinnamic acid moiety generates the optical anisotropy of the film. When the exposed film is annealed or a virgin film is exposed to LPUV light at elevated temperatures, molecular reorientation both perpendicular and parallel to the polarization (E) of LPUV light is achieved, and the generated birefringence is 0.15. The orientation behavior of the film is determined by polarization UV and FTIR spectroscopies. Furthermore, the molecular orientation is erased by annealing at elevated temperature, while reexposing to LPUV light reorganizes the orientation. Finally, homogeneous alignment control of low-molecular liquid crystals on P...