Hwang Yong Jae, Hong Sung Hwan, Lee Sang Gu, Cho Moon Hyung, Shin Dong Myung
Department of Chemical Engineering, Hong-ik University, Seoul 121-791, Republic of Korea.
Ultramicroscopy. 2008 Sep;108(10):1266-72. doi: 10.1016/j.ultramic.2008.04.082. Epub 2008 May 15.
The surface characteristics of polyimide films containing cinnamate groups which promote the uniform alignment in adjacent liquid crystal (LC) upon photodimerization by linearly polarized ultraviolet (LPUV) lights were studied [M. Schadt, K. Schmitt, V. Koznikov, V. Chignirov, Jpn. J. Appl. Phys. 31 (1992) 2155.]. But photoalignment methods have an image sticking problem by un-reacted photosensitive functional groups, which can be a severe defect to achieve high reliability of liquid crystal display (LCD) panels. So the un-reacted photosensitive functional groups were deactivated using bromine or ethanethiol. Bromine and ethanethiol lead to the formation of carbon-bromine or carbon-sulfur bonds from carbon-carbon double bonds. The interfacial reaction of bromine or ethanethiol on the polyimide surface has been studied using in situ X-ray photoelectron spectroscopy (XPS). The change of surface tension was observed by using a contact angle analyzer. The photoelastic modulator (PEM) was used to analyze the optical anisotropy on the polyimide surface. Also, the atomic force microscopy (AFM) was used to observe the morphology of polyimide surface [K. Rajesh, M.K. Ram, S.C. Jain, S.B. Samanta, A.V. Narliker, Thin Solid Films 325 (1998) 251.].
研究了含肉桂酸酯基团的聚酰亚胺薄膜的表面特性，该基团在通过线偏振紫外光（LPUV）进行光二聚化时能促进相邻液晶（LC）的均匀排列[M. Schadt, K. Schmitt, V. Koznikov, V. Chignirov, Jpn. J. Appl. Phys. 31 (1992) 2155.]。但是光取向方法存在未反应的光敏官能团导致的图像残留问题，这对于实现液晶显示器（LCD）面板的高可靠性可能是一个严重缺陷。因此，使用溴或乙硫醇使未反应的光敏官能团失活。溴和乙硫醇会使碳 - 碳双键形成碳 - 溴键或碳 - 硫键。已使用原位X射线光电子能谱（XPS）研究了溴或乙硫醇在聚酰亚胺表面的界面反应。使用接触角分析仪观察表面张力的变化。使用光弹性调制器（PEM）分析聚酰亚胺表面的光学各向异性。此外，使用原子力显微镜（AFM）观察聚酰亚胺表面的形态[K. Rajesh, M.K. Ram, S.C. Jain, S.B. Samanta, A.V. Narliker, Thin Solid Films 325 (1998) 251.]。
