V-shaped Schiff’s base liquid crystals based on resorcinol: synthesis and characterisation

This paper designed and synthesised a series of V-shaped liquid crystal molecules (<b>X-SBA_nE</b>) with resorcinol as the core and Schiff base as the mesogenic arms (<b>X-SBAA</b>_<b>n</b>). The effects of polarity of terminal groups (X=-CH₃O,-CH₃,-Cl) and length of flexible chain (n = 4,6,8) on mesogenic ranges were discussed. The chemical structure of <b>X-SBAA</b>_<b>n</b> and <b>X-SBA_nE</b> was studied using FT-IR and ¹H-NMR while their thermal behaviour and mesogenic ranges were investigated via differential scanning calorimetry (DSC) and polarising optical microscopy (POM). The results indicated that <b>X-SBAA</b>_<b>n</b> containing OCH₃ and Cl substituents exhibited mesophase except for the analogue having CH₃ substituent which was found to be non-mesogenic. All of the synthesised <b>X-SBA_nE</b> had liquid crystal properties and exhibited nematic phases in heating and cooling. The length of the flexible spacers and terminal groups significantly influenced their mesogenic ranges.