Landau expansion coefficients related to second order SmA-SmC* transition for ferroelectric liquid crystal mixtures composed from an achiral matrix and chiral dopants

Abstract

A new three component ferroelectric liquid crystal mixture FLC-441 showing the second order phase transition and large electroclinic response with microsecond switching times have been studied with an aim to determine the Landau expansion coefficients. Capacitance, tilt angle and polarization measurements were performed in the smectic A and smectic C phases to obtain these coefficients. Unexpectedly, very small values of first Landau coefficient (α) has been obtained not previously reported in literature for any other substance. A new molecular approach to design the mixtures has been attributed to the small value of first Landau coefficient obtained.