Pretilt Angle Generation on Photoreactive Polymer Films
Pretilt Angle Generation on Photoreactive Polymer Films
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光反应聚合物薄膜上的预倾角生成
DOI：
10.1103/physreve.58.3295
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
Jianmin Chen
中科院分区：
文献类型：
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作者：
H. G. Galabova;D. Allender;Jianmin Chen
研究了线偏振紫外光和紫外光双重照射光反应性聚合物薄膜时液晶预倾角产生的机理。第一次曝光的时间是垂直于表面的，随后用偏振平面相对于第一次紫外光的偏振平面旋转90°的倾斜入射的紫外光照射膜时间是1/2。两次曝光后的聚合物膜的状态的特征在于与张量序参数，然后作为边界条件的表面状态的液晶。用扩展的Landau-de Gennes理论研究了体相液晶行为，该理论考虑了弱表面相互作用与张量序参量呈线性关系的可能性。计算预倾角作为λ 1和λ 2的函数，以及作为第二紫外光入射角的函数。预倾角的计算行为被认为是在定性与实验观察。还得出了关于锚固强度的结论。
The mechanism of liquid crystal pretilt angle generation on photoreactive polymer films doubly exposed to linearly polarized ultraviolet ͑uv͒ light has been investigated. The first exposure for time 1 is normal to the surface, and the film is subsequently irradiated for time 2 with obliquely incident uv light with a plane of polarization rotated by 90° with respect to that of the first uv light. The state of the polymer film after two exposures was characterized with a tensor order parameter, which then served as a boundary condition for the surface state of the nematic liquid crystal. The bulk liquid crystal behavior was investigated using Landau–de Gennes theory extended to include the possibility for weak surface interactions linear in the tensor order parameter. The pretilt angle was calculated as a function of both 1 and 2 , and as a function of the second uv light angle of incidence. The calculated behavior of the pretilt angle was found to be in qualitative agreement with experimental observations. Conclusions about the strength of the anchoring have also been made.