各向异性光交联作用对液晶在起伏光栅表面的取向影响  

Effect of Anisotropic Photo-crosslinking on Liquid Crystal Alignment with Duplicated Surface-relief-gratings

作　　者：郭妙才[1,2] 和亚宁[1] 王晓工[1] 

机构地区：[1]清华大学化工系高分子研究所,北京100084 [2]中航复合材料有限责任公司/中航复合材料技术中心、先进复合材料重点实验室,北京100095

出　　处：《高等学校化学学报》2015年第4期751-757,共7页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:51061130556)资助~~

摘　　要：以含肉桂酸基团的光敏聚酰亚胺为'墨水',通过软印刷技术制备了一种新型的可进一步光交联的表面起伏光栅,研究了各向异性光交联对光栅热稳定性和光栅诱导液晶取向的影响.研究结果表明,在经过紫外光交联后,光栅的热稳定性有较大提高,在经过高于未交联聚酰亚胺的玻璃化转变温度31℃处理2 h后,光栅形貌未发生变化.曝光前后光栅都能诱导液晶分子在表面均一沿面排列.当线性偏振紫外光的偏振方向与光栅沟槽垂直时,光交联能促进光栅对液晶的定向能力,反之则降低的定向能力.通过改变辐照光的偏振方向,调节光栅深度,能控制液晶分子在光栅上的取向方向.将这种软印刷得到的光栅用作液晶定向层,不仅可具有更好的热稳定性和定向能力,还可以调节液晶分子在光栅上的取向方向,实现多畴取向.Surface-relief-gratings with further photo-crosslinkable property were prepared by softlithography using photo-sensitive polyimide containing cinnamate groups as ＂ink ＂. The effect of anisotropic photocrosslinking on the thermos-stability of gratings and the alignment of liquid crystal（ LC） on gratings was studied. The thermos-stability of the photo-cured gratings was significantly increased. No shape deformation was observed for the gratings after treated at a temperature 31 ℃ above the glass transition temperature of the uncured polyimide. Both the un-exposed and exposed gratings induced uniform LC alignment on their surfaces.By irradiation with linear polarized UV light perpendicular to the gratings grooves,the LC alignment was enhanced. By changing the polarized direction of the UV light and controlling the depths of gratings,the LC alignment direction on the gratings was adjusted. This study result shows that the photo-crosslinkable gratings can achieve better thermo-stability,better LC alignment and adjustable aligned direction to achieve multi-domain alignment. The above research can lead to further understanding of the LC alignment mechanism.

关 键 词：聚酰亚胺 各向异性光交联 液晶取向 软刻蚀 表面起伏光栅 

分 类 号：O63[理学—高分子化学]