Influence of SiO2 nanoparticles on the dielectric properties and anchoring energy parameters of pure ferroelectric liquid crystal

Abstract

In this study, we have investigated the electrical and anchoring energy of ferroelectric liquid crystal (FLC) with the dispersion of SiO2 nanoparticles (NPs). Due to their higher average spontaneous polarization and helical arrangement of FLC molecules, the molecules strongly interacted to SiO2 NPs which increased the value of dielectric permittivity and anchoring energy parameters as demonstrated by the dielectric and electro-optic properties measurement. This two-dimensional array of molecules has been exploited through the study of dielectric permittivity and dielectric loss in presence of silica NPs from low frequency regime to high frequency region in deep smectic phase. In present work we reported dielectric and electro-optical parameters for pristine FLC and SiO2+FLC composites (0.5% and 1.0% wt/wt concentrations of SiO2 NPs). The dielectric permittivity and dielectric loss have been calculated from the measurement of capacitance and conductance with variation of frequency and concentration of NPs as well. The dispersion and polarization anchoring energy coefficients have been calculated from electro-optic properties measurement with the function of applied voltage for pure and SiO2+FLC composites. The dielectric permittivity has increased with the dispersion of SiO2 NPs in pure FLC matrix and relaxation frequency shifted towards high and low frequency region for low (0.5%) and high (1.0%) concentrations of NPs. The spontaneous polarization of SiO2+FLC composites is increased as compared to pure FLC. The experimental results are explained on the basis of different intermolecular interactions arising between FLC molecules and SiO2 NPs.