Effect of spacer length on mesomorphic behaviours of chiral liquid crystal compounds containing (-)-menthyl |
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| Authors: | Cong-Cong Luo Qing-Lin Meng Gui-Yang Yan Ying-Gang Jia |
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| Institution: | 1. College of Science, Northeastern University, Shenyang, People’s Republic of China;2. Fujian Provincial Key Laboratory of Featured Materials in Biochemical Industry, Ningde Normal University, Ningde, People’s Republic of China |
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| Abstract: | ABSTRACTA homologous series of new chiral liquid crystal compounds, MnBEB (n = 4–10), was prepared by covalently linking a chiral (–)-menthyl with biphenyl-benzoate via a dicarboxylic spacer of varying length and parity. A combination of analysis methods, such as FT-IR, 1H NMR spectra, differential scanning calorimetry (DSC), polarised optical microscopy (POM) and X-ray diffraction was carried out to systematically investigate their phase structures and phase transition behaviours. The length and parity of the flexible spacers has a profound influence on the Tm and Tc and a modest odd-even effect is observed for the chiral liquid crystal compounds MnBEB. Only compound M4BEB developed an N* phase with selectively reflection on heating and a blue phase on cooling process. In addition, increasing the length of the flexible spacers tends to narrow the temperature range of the N* phase and widen the smectic phase, moreover, the pitch becomes longer with the spacer increases. |
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| Keywords: | (–)-Menthol chiral liquid crystal spacer length odd-even effect blue phase |
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