Electro-Optical Behavior of a High Birefringence Mesogenic Mixture

Abstract

Liquid crystal mixtures tailored to possess high birefringence (Δn ≥ 0.30) are being currently used extensively in photonic devices. The present work entails the study of electro-optical properties of such a high birefringence mixture (code name: 1770-2). The multicomponent thermotropic mixture, composed of compounds belonging to families of alkylfluoroisothiocyanatotolanes and alkylphenylfluoroisothiocyanatotolanes, exhibits only the nematic mesophase. The thermal variation of electric permittivities (ϵ_| and ϵ_⊥) at different frequencies has been determined. Using the birefringence data, thermal variation of polarizability has been determined. The variation of the effective average molecular dipole moment μ_sol of the set-up molecules in solutions of varying concentrations (in%wt) at a particular temperature has been determined and the average molecular dipole moment μ_iso of the set-up molecules has been obtained. With a view to determine the nature of the molecular association in the mesophase, the molecular correlation factors “g” has been estimated from measurement of average dipole moment of the set-up molecules.

Keywords:

• Correlation factor
• dipole moment
• electric permittivity
• liquid crystal mixture
• polarizability