The Study of Bisimidazolium Ionic Liquid Crystals Containing Oligo-ether Group

• Main Authors: Tsung- Shun Lei, 雷宗舜
• Other Authors: Jung-Nan Chen
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/57078194080274242295

碩士 === 輔仁大學 === 化學系 === 89 === The aim of this work is to synthesize and investigate liquid crystalline properties of bisimidazolium salts containing oligo-ether group {[(Cn-Im)2-EOq]Cl2‧xH2O， n＝18、16、14、12、10、8； q＝1、2、3， x=2，4}. One compound, [(C14-Im)2-EO1]Cl2‧2H2O was structurally determined by single crystal X-ray diffraction. The hydrogen bonding was the major interaction force in this single crystal. The bisimidazolium salts were prepared by the literature's methods with slight modification. Liquid crystalline behaviors of these compounds were investigated by differential scanning calorimetry, polarized optical microscopy, and X-ray diffraction. The typical fan texture, the spontaneous homeotropic behavior, and the powder X-ray diffraction results suggest a smectic mesophase. Both the melting and isotropic transition temperatures increase with the alkyl chain lengths, but lower transition temperatures are observed with the increasing number of oligo-ether groups. All of these compounds have good thermal stability and wide liquid crystalline range. For compound of n=12 and 10, are highly viscous room temperature liquid crystals. For compound of n=8, only crystal phase is observed.