The Characteristics of Polymer LB Films Aligned Ferroelectric Liquid Crystals
- Received Date: 1999-03-30
Abstract: Newly-synthesized polyimide(PI) LB films were deposited and used to align ferroelectric liquid crystals(FLCs).Atomic force microscope was used to investigate the morphology of PI LB films.It is found that LB films show different crystalline structure when they were treated by the different imidization temperatures.The LB films imidized at the high temperature show the orderly oriented polymer chain structure on the sustrate surfaces while the low temperature treated LB films show an irregular amphours-like aggregate structure.It demonstrates that these two types of PI LB films show different surface orderness and crystallinity.The surface-stabilized FLC cells that are aligned by the high temperature imidized PI LB films have the fast response times of 80 and 90μs to the rising and decaying stages respectively and an excellent bistability to the completeness,while the cells which are aligned by the low temperature imidized PI LB films show slower response times longer than 1ms and the incomplete memory capability.According to the AFM observations and the charge-transfer model in the interface between LB alignment films and the FLC layer,it is regarded that the LB films imidized at the high temperature can provide a higher energy barrier than that of imidized at the low temperature,which facilitates the appearance of FLC bistability.In addition,the ultra-thinness of LB films is beneficial for the neutralization and release of the surface charges brought out during the switching process,which guarantees the obtainment of excellent bistable memory capability and the realization of fast response up to micro-seconds in the surface-stabilized FLC devices.
|Citation:||Lu Ruibo, Xu Keshu, Zhang Shuyan, Zhang Yandong, Xing Zhongjin, Gu Jianhua, Deng Huihua, Lu Zuhong. The Characteristics of Polymer LB Films Aligned Ferroelectric Liquid Crystals[J]. Chinese Journal of Chemical Physics , 2000, 13(1): 103-108. doi: 10.1088/1674-0068/13/1/103-108|