Thermal and Optical Stabilities of Photoisomerizable Polyimide Layers for Nematic Liquid Crystal Alignments
Thermal and Optical Stabilities of Photoisomerizable Polyimide Layers for Nematic Liquid Crystal Alignments
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用于向列液晶排列的光致异构化聚酰亚胺层的热稳定性和光学稳定性
DOI：
10.1143/jjap.37.5663
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发表时间：
1998
影响因子：
1.5
通讯作者：
Hideo Takezoe Hideo Takezoe
中科院分区：
文献类型：
--
作者：
Byoungchoo Park Byoungchoo Park;Youngyi Jung Youngyi Jung;Hyun;Ha;Youngkyoo Kim Youngkyoo Kim;Sooman Lee Sooman Lee;Sei;Masa;Hideo Takezoe Hideo Takezoe
我们研究了非晶液晶光取向膜的热稳定性和光稳定性。对于光致取向层，三种光致异构聚合物系统进行了研究：掺杂有偶氮苯分子的聚酰胺酸，侧链取代的聚酰胺酸与偶氮苯单元，和主链取代的聚酰胺酸与偶氮苯单元。光致各向异性产生的照明与线偏振近紫外光从汞灯，并通过测量偏振紫外吸收光谱和光学双折射进行评估。使用在各种热和光学条件下加工的光配向层研究了DLC配向特性。观察到主链聚酰亚胺系统表现出良好的单向LC取向和优异的热稳定性（300°C下1小时）和光学稳定性。此外，我们提出了一个新的程序，其中的光照射过程进行之前的热亚胺化过程，以实现稳定的光取向层。
We have investigated the thermal and optical stabilities of the photoalignment layers for nematic liquid crystals (LCs). For the photoalignment layers, three kinds of photoisomerizable polymer systems were studied; a polyamic acid doped with azobenzene molecules, a side-chain-substituted polyamic acid with azobenzene units, and a main-chain-substituted polyamic acid with azobenzene units. Photoinduced anisotropy was produced by illumination with linearly polarized near-UV light from a mercury lamp, and evaluated by measuring polarized UV absorption spectra and optical birefringence. The nematic LC-alignment properties were investigated using the photoalignment layers processed under various thermal and optical conditions. It was observed that the main-chain polyimide system exhibited good unidirectional LC alignment and excellent thermal (300°C for 1 h) and optical stabilities. Moreover, we suggest a new procedure, in which the photoillumination process is carried out before the thermal imidization process, to achieve a stable photoalignment layer.