Enhancement of the stability and temperature range of the mesophases in the binary mixtures of cholesteryl myristate and 4-n-decyloxy benzoic acid

Abstract

Thermodynamical, optical, and electrical properties of the binary mixtures of cholesteryl myristate (ChM) and 4-n-decyloxybenzoic acid (DOBA) have been carried out by the differential scanning calorimeter, polarized optical microscopy (POM), and impedance spectroscopy. Through thermodynamic study, various phase transition temperatures, transition enthalpies, and transition entropies have been determined to investigate temperature range and stability of the mesophases of the mixtures. Phase diagrams in the heating and cooling cycles have been drawn for the ChM–DOBA binary system. Optical textures of different mesophases have identified with the help of POM. Dielectric permittivity has been determined in planar and homeotropic alignments of the mixtures having DOBA concentrations 30.0 and 92.3 mol %. The experimental dielectric data in the frequency range of 1 Hz to 35 MHz do not show any relaxation mode in both the alignments of these mixtures. Dielectric anisotropy has been determined for the various observed phases of the mixtures.