Correlation between the molecular chirality index and the spontaneous polarisation in series of smectic C* liquid crystals

Abstract

A correlation between spontaneous polarisation and the chirality index of the constituent molecules, multiplied by the molecular transverse dipole, has been considered for five series of ferroelectric smectic C* liquid crystals. A good correlation has been found within each series, and it has been shown that the scaled chirality index may be used to estimate the spontaneous polarisation in a series of smectic C* mesogens with small systematic changes of the molecular structure. At the same time one cannot expect any significant correlation between the polarisation and the chirality index for smectic C* materials of sufficiently different structure because the spontaneous polarisation may be significantly effected by some details of the molecule's structure including the orientation of the transverse dipole with respect to the primary short molecular axis.

Keywords:

• ferroelectric liquid crystals
• chirality index
• molecular structure

Acknowledgement

This work has been undertaken during the stay of M.A. Osipov at the University of Stuttgart as a Mercator Guest Professor supported by DFG.