Application of thermodynamic model to study the electro-optical and structural properties of ferroelectric liquid crystal W-212

Abstract

In this paper, we have studied the influence of temperature on spontaneous polarization, tilt angle and pitch of chiral smectic C (Sm C*) phase in the vicinity of chiral smectic A to chiral smectic C (Sm A*–Sm C*) phase transition in a ferroelectric mesogen W-212 by employing the Landau-de-Gennes type free-energy density expansion (thermodynamic model). In this model the free-energy density of the system is written as an expansion in terms of tensor orientational order (Formula presented.), the scalar smectic order (Formula presented.), the polarization vector P, the wave vector q, and their mutual coupling terms. The values of Landau coefficients associated with various order parameter terms have been determined from the experimentally measured properties. Using these values of coefficients, the temperature variations of spontaneous polarization, tilt angle and pitch have been evaluated. A close agreement between experimental results and theoretical predictions have been found. © 2025 Informa UK Limited, trading as Taylor & Francis Group.