Highly Ordered In-Plane Photoalignment Attained by the Brush Architecture of Liquid Crystalline Azobenzene Polymer
Highly Ordered In-Plane Photoalignment Attained by the Brush Architecture of Liquid Crystalline Azobenzene Polymer
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DOI：
10.1021/ma802010x
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发表时间：
2009-01
期刊：
影响因子：
5.5
通讯作者：
Takayuki Uekusa;Shusaku Nagano;T. Seki
中科院分区：
文献类型：
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作者：
Takayuki Uekusa;Shusaku Nagano;T. Seki
通过表面引发原子转移自由基聚合(ATRP)，在石英或硅衬底上制备了含偶氮(Az)介晶基团的液晶聚合物刷。接枝链长受聚合时间和单体初始浓度的控制。接枝链膜为Smectec LC相，接枝链中偶氮杂环己烷的分子取向与衬底平面基本平行。通过偏振UV、−-Vis吸收光谱和掠入射X射线衍射仪评价了液晶聚合物刷的面内光取向行为。线偏振可见光的照射很容易使接枝链中的Az介质物具有高度有序的面内光排列，这是由于平行于衬底排列的Az介质物对光的有效吸收。在略高于聚合物Tg的温度下，产生最高的面内取向度。结果表明，单结晶态液晶聚合物具有较高的稳定性。
We newly prepared liquid crystalline (LC) polymer brushes containing an azobenzene (Az) mesogenic moiety on a quartz or silicon substrate by surface-initiated atom transfer radical polymerization (ATRP). The grafted chain length was controlled by polymerization time and initial monomer concentration. The grafted chain film adopted a smectec LC phase and the molecular orientation of Az mesogens in the grafted chain was nearly parallel to the substrate plane. The in-plane photo-orientation behavior of LC polymer brushes was evaluated by polarized UV−vis absorption spectoscopy and grazing incidence X-ray diffraction measurements. Highly ordered in-plane photoalignment of Az mesogens in the grafted chain was readily provided by the irradiation with linearly polarized visible light due to the effective light absorption of the Az mesogens aligned parallel to the substrate. The highest degree of in-plane orientation was generated at a temperature slightly above Tg of the polymer. As a result, monodomain LC polym...