Chromonic liquid crystalline phase transition involving a biphasic region of nematic and hexagonal phases

Abstract

We report the results of our studies on the optical and thermal properties of binary mixture of two compounds viz. abietic acid and poly ethylene glycol (PEG). The mixture shows a very interesting co-existent biphasic region of lyotropic nematic (N + I) and intermediate hexagonal (M + I) phases, sequentially when the specimen is cooled from its isotropic phase at different concentrations of abietic acid in PEG. The aggregated molecular size has been confirmed by X-ray studies. The temperature variation of optical anisotropy, electrical conductivity, ultrasonic velocity, and molar and adiabatic compressibility has also been discussed.

Keywords:

• binary mixture
• columnar phase
• lyotropic chromonic
• molecular aggregation
• nematic
• optical anisotropy
• ultrasonic velocity