Modification in different physical parameters of orthoconic antiferroelectric liquid crystal mixture via the dispersion of hexanethiol capped silver nanoparticles

Abstract

Herein we investigate an orthoconic anti ferroelectric liquid crystal (OAFLC) material, W1000 and its mixtures with the dispersion of hexanethiol capped silver nanoparticles (Ag NPs) in three different concentrations of 0.1 wt%, 0.25 wt% and 0.50 wt%. The pristine AFLC and its mixtures are characterized by the dielectric, electro-optical and spectroscopic techniques. Various parameters viz. dielectric permittivity, electrical conductivity, spontaneous polarization, rotational viscosity, response time, anchoring energy coefficients, and photoluminescence of the pristine AFLC are altered due to the addition of Ag NPs. The polarizing optical micrographs show modification in the molecular distribution of the host AFLC after the addition of Ag NPs. The spontaneous polarization of the Ag NPs dispersed system was reduced due to the anti-parallel correlation amid dopant and AFLC dipoles as a consequence the dielectric permittivity of the Ag NPs-AFLC mixtures has also been decreased. The electrical conductivity of the pristine AFLC has increased after the dispersion of Ag NPs. Faster switching response of Ag NPs dispersed system comparing to that of the pristine AFLC is manifested by the decrement in the rotational viscosity. The anchoring energy coefficients were found to be reduced for the Ag NPs dispersed system. The photoluminescence (PL) intensity of the pristine AFLC material has been enhanced after the dispersion of Ag NPs which strongly depends upon the dopant concentration. Faster switching response, enhanced electrical conductivity and PL Intensity of the Ag NPs-AFLC mixtures are the remarkable findings of this study.