Thermotropic, refracting and birefringent properties in homogeneous mixtures of 4-n-alkyl-4 '-cyanobiphenyl mesogens

Abstract

In this work, studies of the thermotropic and thermo-optical properties in five homogeneous mixtures of 4-n-alkyl-4'-cyanobiphenyl mesogens have been carried out. Temperature behavior of the mean refractive index n, ordinary n(o) and extraordinary n(e) refractive indices has been investigated. The principal polarizabilities alpha(0) and alpha(e), effective geometry parameter alpha(eg) and average polarizability alpha(ave) were calculated using the internal field model (Vuks approach). Behavior of the birefringence Delta n and the anisotropy of polarizability Delta alpha as a function of temperature, and the order parameter in regions of the smectic A-nematic, nematic-isotropic liquid and smectic A-isotropic liquid phase transitions are discussed. (C) 2015 Published by Elsevier B.V.