Mesomorphism in a binary mixture of non-mesogens: A thermo-physical study

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Abstract

A comprehensive study on a liquid crystal formed by mixing two non-mesogens, viz., cholesterol and cetyl alcohol has been carried out. Polarized microscopic observations confirmed that the mixture exhibits smectic A phase below 48.2 °C. The mechanism possible for the formation of ordered liquid crystal phase when two non-mesogens are mixed is discussed. Density measured using a precision density meter was found to drop drastically in the vicinity of isotropic to smectic A transition temperature. The density fluctuations at the transition are discussed on the basis of: (i) the long wavelength limit of the structure factor and (ii) the critical exponent evaluated using modified Landaude Gennes theory. The ultrasound velocity, determined using the interferometer method, drops drastically near the smectic Aisotropic transition temperature. The temperature-dependent data of density and ultrasound velocity enabled the evaluation of the adiabatic compressibility and acoustic impedance. The specific heat at constant pressure measured using differential scanning calorimetry shows a large increase in the vicinity of the phase transition. A correlation of thermodynamic functions to thermo-elastic properties was established through thermodynamic route. This relationship, along with experimentally measured quantities forms the basis for the thermo-physical characterization of the mixture. This facilitated the evaluation of specific heat at constant volume, the ratio of specific heats, the isothermal compressibility and the Grneisen parameter across the smectic Aisotropic phase transition.

Original languageEnglish
Pages (from-to)4586-4593
Number of pages8
JournalPhysica B: Physics of Condensed Matter
Volume405
Issue number21
DOIs
Publication statusPublished - Nov 1 2010

Fingerprint

Binary mixtures
binary mixtures
Specific heat
Liquid Crystals
Compressibility
Liquid crystals
Superconducting transition temperature
specific heat
Ultrasonics
Phase transitions
Thermodynamics
compressibility
Acoustic impedance
Cholesterol
transition temperature
liquid crystals
Interferometers
thermodynamics
acoustic impedance
evaluation

Keywords

  • Acoustic impedance
  • Adiabatic compressibility
  • Grneisen parameter
  • Mesomorphism
  • Specific heat ratio

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

Cite this

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title = "Mesomorphism in a binary mixture of non-mesogens: A thermo-physical study",
abstract = "A comprehensive study on a liquid crystal formed by mixing two non-mesogens, viz., cholesterol and cetyl alcohol has been carried out. Polarized microscopic observations confirmed that the mixture exhibits smectic A phase below 48.2 °C. The mechanism possible for the formation of ordered liquid crystal phase when two non-mesogens are mixed is discussed. Density measured using a precision density meter was found to drop drastically in the vicinity of isotropic to smectic A transition temperature. The density fluctuations at the transition are discussed on the basis of: (i) the long wavelength limit of the structure factor and (ii) the critical exponent evaluated using modified Landaude Gennes theory. The ultrasound velocity, determined using the interferometer method, drops drastically near the smectic Aisotropic transition temperature. The temperature-dependent data of density and ultrasound velocity enabled the evaluation of the adiabatic compressibility and acoustic impedance. The specific heat at constant pressure measured using differential scanning calorimetry shows a large increase in the vicinity of the phase transition. A correlation of thermodynamic functions to thermo-elastic properties was established through thermodynamic route. This relationship, along with experimentally measured quantities forms the basis for the thermo-physical characterization of the mixture. This facilitated the evaluation of specific heat at constant volume, the ratio of specific heats, the isothermal compressibility and the Grneisen parameter across the smectic Aisotropic phase transition.",
keywords = "Acoustic impedance, Adiabatic compressibility, Grneisen parameter, Mesomorphism, Specific heat ratio",
author = "George, {A. K.} and Singh, {R. N.} and S. Arafin and C. Carboni and {Al Harthi}, {S. H.}",
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T2 - A thermo-physical study

AU - George, A. K.

AU - Singh, R. N.

AU - Arafin, S.

AU - Carboni, C.

AU - Al Harthi, S. H.

PY - 2010/11/1

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N2 - A comprehensive study on a liquid crystal formed by mixing two non-mesogens, viz., cholesterol and cetyl alcohol has been carried out. Polarized microscopic observations confirmed that the mixture exhibits smectic A phase below 48.2 °C. The mechanism possible for the formation of ordered liquid crystal phase when two non-mesogens are mixed is discussed. Density measured using a precision density meter was found to drop drastically in the vicinity of isotropic to smectic A transition temperature. The density fluctuations at the transition are discussed on the basis of: (i) the long wavelength limit of the structure factor and (ii) the critical exponent evaluated using modified Landaude Gennes theory. The ultrasound velocity, determined using the interferometer method, drops drastically near the smectic Aisotropic transition temperature. The temperature-dependent data of density and ultrasound velocity enabled the evaluation of the adiabatic compressibility and acoustic impedance. The specific heat at constant pressure measured using differential scanning calorimetry shows a large increase in the vicinity of the phase transition. A correlation of thermodynamic functions to thermo-elastic properties was established through thermodynamic route. This relationship, along with experimentally measured quantities forms the basis for the thermo-physical characterization of the mixture. This facilitated the evaluation of specific heat at constant volume, the ratio of specific heats, the isothermal compressibility and the Grneisen parameter across the smectic Aisotropic phase transition.

AB - A comprehensive study on a liquid crystal formed by mixing two non-mesogens, viz., cholesterol and cetyl alcohol has been carried out. Polarized microscopic observations confirmed that the mixture exhibits smectic A phase below 48.2 °C. The mechanism possible for the formation of ordered liquid crystal phase when two non-mesogens are mixed is discussed. Density measured using a precision density meter was found to drop drastically in the vicinity of isotropic to smectic A transition temperature. The density fluctuations at the transition are discussed on the basis of: (i) the long wavelength limit of the structure factor and (ii) the critical exponent evaluated using modified Landaude Gennes theory. The ultrasound velocity, determined using the interferometer method, drops drastically near the smectic Aisotropic transition temperature. The temperature-dependent data of density and ultrasound velocity enabled the evaluation of the adiabatic compressibility and acoustic impedance. The specific heat at constant pressure measured using differential scanning calorimetry shows a large increase in the vicinity of the phase transition. A correlation of thermodynamic functions to thermo-elastic properties was established through thermodynamic route. This relationship, along with experimentally measured quantities forms the basis for the thermo-physical characterization of the mixture. This facilitated the evaluation of specific heat at constant volume, the ratio of specific heats, the isothermal compressibility and the Grneisen parameter across the smectic Aisotropic phase transition.

KW - Acoustic impedance

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KW - Specific heat ratio

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