Dependence of the SmC* layer reorientation dynamics on enantiomeric excess

Abstract

The process of the in-plane reorientation of smectic layers under application of asymmetric electric fields was investigated with respect to the enantiomeric excess. Measurements were carried out as a function of electric field asymmetry ratio, electric field amplitude and temperature. The enantiomeric excess was varied by mixing chiral antipodes of a ferroelectric smectic C* liquid crystal. We observed the general dynamic behaviour previously reported for a variation of external parameters: increasing layer reorientation velocity with increasing field asymmetry and amplitude and strongly decreasing layer reorientation velocity for decreasing temperature in the SmC* phase. The smectic layer reorientation dynamics is found to be slowed down linearly by decreasing the enantiomeric excess. The rotation vanishes on approaching the racemic mixture. The layer reorientation process changes its direction as the racemic composition of enantiomers is crossed.