Impact of ferroelectric nanoparticles on the ordering behavior and electric response of a liquid crystal near the isotropic-smectic A transition

Abstract

ABSTRACT We present a theoretical study of the electric behaviour of a ferroelectric liquid crystal (FLC) doped with ferroelectric nanoparticles (FNPs). According to the recent reports on industrial developments based on liquid crystal materials, FLCs are increasingly used not only in displays but also in preparing new materials with unconventional properties. In this work, we focus on the anomalies caused by the nanoparticles on ordering behaviour, dielectric permittivity, and polarization of the system, as well as the pre-transitional effects near the Isotropic-Smectic A (I-SmA) phase transition. We obtain the polarization of a nano-doped system under an applied electric field and discuss the influence of the concentration of nanoparticles on the phase transition for both isotropic and mesomorphic phases. The calculations are based on the phenomenological Landau theory. Our results show weak induced orientational order in the isotropic phase of the I-SmA phase transition. Considering the Kerr effect in the nano-doped system under the influence of macroscopic polarization, we find that the FNPs significantly affect such induced orientational behaviour. Our results confirm a pre-transitional anomaly of dielectric permittivity for the I-SmA phase transition. The strong influence of nanoparticles on the pre-transitional behaviour in both isotropic and mesomorphic phases is also revealed.