Synthesis and mesomorphic properties of two series of new azine‐type liquid crystals

Abstract

Two series of symmetrical azine‐type liquid crystals were synthesised and their chemical structures identified by FTIR, 1H NMR and elemental analysis. Their mesomorphic properties were investigated by polarising optical microscopy, differential scanning calorimetry and X‐ray diffraction. The characteristic of these liquid crystals is that they have a high clearing point (most were higher than 320°C) and a broad thermal range in the mesophase. The end groups of the liquid crystals had an effect on their mesomorphic properties. The series with alkoxy end groups all exhibited both smectic A (SmA) and a nematic phase, whereas the series with alkyl end groups showed only nematic phase at their lower analogues and showed both SmA and nematic properties at their higher analogues.