Thermodynamic study of a plastic columnar discotic material 2, 3, 6, 7, 10, 11-hexabutyloxytriphenylene dispersed with gold nanoparticles under elevated pressure.

Abstract

We report a systematic work on the effect of pressure on thermodynamic properties of a plastic columnar discotic liquid crystal (DLC), namely 2, 3, 6, 7, 10, 11-hexabutyloxytriphenylene (HAT4) dispersed with gold nanoparticles up to 1000 MPa by using a high-pressure differential scanning calorimeter. The goal is to determine how elevated pressure can be used to modify the physical properties of plastic columnar DLC and their nanocomposites via changes in inter- and intra-molecular distances of discotics. We find that the columnar hexagonal plastic to isotropic liquid (Colhp–IL) phase transition temperatures and enthalpy decrease with increasing pressure. However, crystal to plastic columnar hexagonal (Cr–Colhp) transition temperature remains almost unchanged for pure and their nanocomposites. The effect of pressure on the phase behaviour of DLC has been studied to elucidate the nature of the mesophase behaviour.