Investigation of liquid crystalline property of a new calamitic liquid crystalline system methyl 4-(4ʹ-(4ʹʹ-(decyloxy)benzyloxy) benzylideneamino)benzoate

ABSTRACT

A new polar calamitic liquid crystal, methyl 4-(4ʹ-(4ʺ-(decyloxy)benzyloxy) benzylideneamino)benzoate (M3BA) containing ether and Schiff base groups as linker with terminal polar ester group, has been synthesised and mesomorphic properties are studied by differential scanning calorimetry, polarising optical microscopy, density functional theory, temperature-dependent X-ray diffraction and temperature-dependent micro- Raman study. The smectic A (SmA) mesophase with focal conic texture has been observed with wide mesomorphic range. Layer thickness in SmA phase is greater than the optimised length of the molecule, indicating partially bilayer SmA phase. Analysis of Raman marker bands of C–H in-plane bending of phenyl rings, C=C stretching of rings, C=N stretching and C=O stretching shows structural changes at molecular level at Cr → SmA phase transition and provides proper intermolecular interactions responsible for dimeric unit in partially bilayer SmA phase.

Graphical Abstract

KEYWORDS:

• Liquid crystals
• smectic A mesophase
• Raman spectroscopy
• XRD
• DFT

Acknowledgements

RN (Senior Research Fellow) is grateful to the University Grants Commission (UGC), India for providing fellowship under Research Fellowship Scheme for Meritorious Students. HKS is grateful to the Council of Scientific and Industrial Research (CSIR), New Delhi, India, for financial support. BS and SKS are grateful to DRDO, India (Project No. ERIP/ER/1203053/M/01/1542) and RKS is thankful to DST for DST-FIST programme.

Disclosure statement

No potential conflict of interest was reported by the authors.

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Funding

RN (senior research fellow) is grateful to the University Grants Commission (UGC), India, for providing fellowship under Research Fellowship Scheme for Meritorious Students. HKS is grateful to the Council of Scientific and Industrial Research (CSIR), New Delhi, India, for financial support. BS and SKS are grateful to DRDO, India (Project No. ERIP/ER/1203053/M/01/1542), and RKS is thankful to DST for DST-FIST programme.