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

ABSTRACT

This paper designed and synthesised a series of V-shaped liquid crystal molecules (X-SBA_nE) with resorcinol as the core and Schiff base as the mesogenic arms (X-SBAA_n). 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 X-SBAA_n and X-SBA_nE 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 X-SBAA_n 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 X-SBA_nE 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.

Graphical abstract

KEYWORDS:

• Synthesis
• V-shaped liquid crystal
• Schiff base
• nematic
• flexible spacers

Supplementary material

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Additional information

Funding

This work was financially supported by the Fundamental Research Funds for the Central Universities [N170504018 and N180705004] and the National Natural Science Fund of China [51273035].