Electro-Optical and Electrical Characteristics of a Hydrodegraded and Recovered Liquid Crystal

• Main Authors: Chun-Tsai Wang, 王俊才
• Other Authors: Wei Lee
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/96233150742962156812

碩士 === 中原大學 === 物理研究所 === 99 === Even though preserved in moisture-proof cabinet, commercial liquid crystals in airtight containers will degrade over time. The degraded liquid crystals exhibit increased conductivity, and the increased content of ion impurities disables their use in fabrication of devices. This thesis aims to discuss the natural aging phenomenon of liquid-crystal materials and to find out the main reason of their deterioration. In addition, the present thesis demonstrates the use of desiccating agents to restore the original electrical characteristics of liquid crystals. The following conclusions can be reached in accordance with the experimental results: 1. Degradation of old liquid crystals in stock often originates from contamination of atmospheric water, causing increase in ion content in the material. 2. Based on the result of a comparative test involving several desiccants of initially identical weight to absorb atmospheric water, the coordination polymer M2B exhibits the highest water-absorption capacity. 3. Our data of dc electro-optical and electrical measurements show that M2B is superior to the molecular sieve MS3 in refreshing the stored liquid crystals. 4. The degraded liquid crystal resembles its fresh counterpart in terms of the voltage holding ratio after 176-h treatment with 30 wt% M2B.