Mesomorphic properties of non-symmetric three-arm chenodeoxycholic acid-derived liquid crystals |
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Authors: | Xin-shi Chen He-zhong Tao Liang Dong Jian-she Hu Dan-shu Yao |
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Affiliation: | 1. Department of Chemistry, College of Science, Northeastern University, Shenyang, People’s Republic of China;2. School of Materials Science and Engineering, South China University of Technology, Guangzhou, People’s Republic of China |
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Abstract: | Six three-arm star-shaped liquid crystals (LCs) based on chenodeoxycholic acid (CDCA), termed as G-BH, G-YD, G-FD, G-DJ, G-DZ and G-BX, respectively, have been synthesised. CDCA was used as the chiral core and the nematic side arm, 6-(4-(ethylbenzoyloxy) phenoxy)-6-oxohexanoic acid, was chosen to be introduced into the two hydroxyl of CDCA to synthesise cholesteric LC (CDCA2EA) and different structures were introduced into the carboxyl group of CDCA to prepare the three-arm star-shaped LCs. Chemical structures and LC properties of the six three-arm LCs were characterised by FTIR, 1H-NMR, differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction and polarised optical microscopy. G-BH and G-DJ displayed cholesteric phase with a long helical pitch; G-BX displayed nematic phase; and G-YD, G-FD and G-DZ displayed cholesteric phase on heating and on cooling. These results indicated that not only the chiral core CDCA but also the structures of the side arms played an important role in inducing the cholesteric phase of the CDCA-derived LCs. G-DZ displayed selective reflection, a wider ?λ and red shift on cooling. |
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Keywords: | Three-arm liquid crystal chenodeoxycholic acid cholesteric phase cholesteric phase with a long helical pitch selective reflection nematic |
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