Influence of flexible chain, polar substitution and hydrogen bonding on phase stability in Shiff based (4)PyBD(4I)BrA-nOBA series of liquid crystals

Krishna Murthy, A V S N and Chalapathy, A V and Srinivasulu, M and Madhumohan, M L N and Rao, Y V and Potukuchi, D M (2018) Influence of flexible chain, polar substitution and hydrogen bonding on phase stability in Shiff based (4)PyBD(4I)BrA-nOBA series of liquid crystals. Molecular Crystals and Liquid Crystals, 664 (1). pp. 46-68. ISSN 1563-5287

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Abstract

Shiff based Linear Hydrogen Bonded Liquid Crystalline homologues, viz., (4)PyBD(4I)BrA-nOBAs for n = 2,3,4,5,6,7,8,10,11 and 12 are synthesized. 1H-NMR and 13C-NMR studies confirm the formation of HBLC and IR confirms the linear hydrogen bonding. Liquid crystal phase abundance, transition temperatures, enthalpy and order of transition are investigated by Polarized Optical Microscopy textural studies and Differential Scanning Calorimetry. Nematic, Smectic-A, -D, -C, Bhexatic, -BCrystal, -F, -I and –G phases are identified. Large LC phase variances, viz., NABhexFG and NACFG are exhibited by intermediate chain length with n = 5 and 6. A-C transition exhibited unique II-order nature. II-order nature for G-Solid transition explained. Phase diagram drawn with flexible chain length infers INA, and ACF and CIF MultiCritical Points and Lifshitz behaviour. NA TriCiritical Point predicted in [3+7] binary. Influences of chain length, linear HB and end polar(-Br) substitution for LC phase stability are is discussed. Results of Phase stability are discussed in the wake of the body of the data and reports in other LCs. DSC enthalpy suggests for utility of intermediate and higher homologues for device savvy tilted Smectic LC phases.

Item Type: Article
Uncontrolled Keywords: Linear Hydrogen bonding, Liquid Crystal phases, longitudinal dipole moment, phase stability
Subjects: Engineering > MIT Manipal > Chemistry
Depositing User: MIT Library
Date Deposited: 27 Jul 2018 05:43
Last Modified: 27 Jul 2018 05:43
URI: http://eprints.manipal.edu/id/eprint/151652

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