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为了制备具有自取向功能的聚酰亚胺(PI)取向膜,避免摩擦工序在取向膜表面造成静电、灰尘、配向不良等不利影响,本实验通过一系列黏度不同且有水平及垂直取向功能的 PI 溶液,研究了 PI 液黏度和其取向膜表面粗糙度的关系,进而研究了 PI 膜表面粗糙度和液晶预倾角(θp )的关系.研究发现：取向膜表面粗糙度随着 PI 液黏度的增大而增大,θp 随着粗糙度的增大而增大,但当粗糙度大于一定值(3．760 nm)后,θp 增长缓慢并趋于稳定.这主要是因为 PI 液黏度增大时,阻碍了相邻 PI 液滴通过分子链段协同运动向彼此扩散的几率,进而形成取向膜表面的“峰谷”形貌,这种“峰谷”形貌表面对液晶垂直取向起到了支撑作用,正是这种支撑作用使得液晶分子获得较大的θp .结合液晶面板响应时间对高预倾角的要求和 Inkjet PI 液滴喷嘴过小对 PI 液黏度的限制,得出 PI 液黏度大约为41CP 时,此时取向膜表面粗糙度为4．830 nm,液晶取向角为5．5°,能较好地满足液晶取向的要求.

To prepare a kind of polyimide (PI)solution with self-alignment function,and avoid produ-cing disadvantage effect (static electricity,particle,alignment error,etc.)on alignment layer with rubbing process,a series of polyimides with different solution viscosity were used to research the rela-tionship between PI solution viscosity and its surface roughness.Meanwhile,the relationship between the surface roughness of PI alignment layer and pretilt angle(θp )of liquid crystal was also studied. The results demonstrated that surface roughness of PI alignment layer increased with PI solution vis-cosity increasing,and also theθp increased with the surface roughness increasing,but when the surface roughness exceeded a certain value of 3.760 nm,θp began to increase slowly.It was mainly be-cause that the high PI solution viscosity hindered the synergic motion of PI chain segment to diffuse to each other,thus forming the rough surface topography.This kind of “peak-valley”topography played a supporting role to the vertical alignment of liquid crystal and then resulted in the highθp .A highθp was generated by high PI solution viscosity to reduce response time,but the micron-grade Inkjet head nozzle would be blocked by high PI solution viscosity.We found that when the viscosity of PI solution was 41CP,its surface roughness of alignment layer was 4.830 nm,and theθp reached to 5.5°,which can satisfy the two requirements mentioned above well.