以6-羥基尼古丁酸為核部分子之掌性液晶合成及其液晶物性之研究

• Main Author: 黃光宇
• Other Authors: 蔡文亮
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/34312726352999058728

碩士 === 國立高雄師範大學 === 化學系 === 91 === Abstract In order to study the influence of the core structure on the phase behavior of the well-known antiferroelectric liquid crystals, (R)-MHPOBC , a series of homologoues containing pyridinyl ring was derived from (R)-2- octanol. New chiral liquid crystals 3a and 3b were synthesized by the esterification of 4-alkoxybiphenyl carboxylic acid 2a or 2b and the chiral phenolic compound 1. The liquid crystal phase sequence of the compound 3a is K─S?─SA─I. Therefore, it is not a ferroelectric liquid crystal. The liquid crystal phase sequence of the compound 3b is K─SCA*─S?─SC*─SA─I. It not only has the property of ferroelectricity but also antiferroelectricity. Our research results indicate that : （1） The length of the terminal achiral chain has a profound effect on the occurrence of SC*, SCA* and SCγ* phase. The reason is still not clear but the conformation change between 3a and 3b seems to be a plausible explaination. （2） The substitution of the phenyl ring of the (R)-MHPOBC structure by the pyridinyl ring does not interrupt the formation of SCA* phase. In comparison to (R)-MHPOBC chiral liquid crystal 3b has a lower phase transition temperature. (R)- MHPOBC 結構 (1)： (2)： (3):