HRTEM, TSC and broadband dielectric spectroscopy of a discotic liquid crystal

Abstract

Due to its molecular configuration, Pyrene 1,3,6,8-tetracarboxylic rac-2-ethyl hexyl ester exhibits a mesomorphic phase at room temperature. High resolution transmission electron microscopy (HRTEM) of samples with various thermal history yield important results on discotic liquid crystal nanostructure. The evolution of the molecular organisation with the temperature has been determined by differential scanning calorimetry (DSC). The physical structure of this columnar liquid crystal is shown by dynamic dielectric spectroscopy (DDS) along a broad temperature and frequency range. As this liquid crystal is used as film electronic devices, the thermostimulated micro-technique (μ-TSC) has been improved and developed. The behavior and molecular mobility in this columnar liquid crystal are studied. The correlation with thermal studies allows us to understand dielectric properties as a function of physical state.