Influence of chirality on the thermal and electric properties of the columnar mesophase exhibited by homomeric dipeptides

Srividhya Parthasarathi, D. S. Shankar Rao, Rashmi Prabhu, C. V. Yelamaggad and S. Krishna Prasad,
J. Chem. Phys. 147, 134905 (2017)

We present the first investigation of the influence of chirality on the thermal and electric properties in a biologically important dipeptide molecule that exhibits a hexagonal columnar liquid crystal phase. The enantiomeric excess, taken as a measure of chirality, is seen to significantly govern various physical parameters, viz., (i) the relaxation frequency and activation energy of a mode that is connected with the antiferroelectric nature of the columnar structure, (ii) the polar order, a measure of which is the magnitude of the axial polarization, (iii) unprecedented level of the enantiomeric dependence of Tc-the columnar-isotropic transition temperature, being more than an order of magnitude larger than seen in the well known rod-like chiral-racemic systems. Dielectric relaxation measurements at elevated pressures on one of the enantiopures and the mixture brings out the feature that the value of activation energy is controlled by the chirality of the medium.