Optical and Dielectric Studies of a Mesogenic Mixture: Determination of Orientational Order Parameter and Angle of Inclination

Abstract

Optical and dielectric studies have been conducted on a liquid crystalline mixture (code name: ZLI 1275) containing phenyl cyclohexane, cyclohexyl phenyl carboxylate, and cyclohexyl benzoate. From optical studies, the orientational order parameter has been determined as a function of temperature and compared with theoretical Maier–Saupe values. The thermal variation of dielectric permittivity has been determined for different operating frequencies and the thermal dependence of the angle of inclination of the effective molecular dipole moment with the director direction has been investigated. Comparison of the optical and dielectric properties of ZLI 1275 has been made with two similar mixtures (ZLI 1701) and (ZLI 1800-000) exhibiting similar nematic temperature ranges and each containing three moieties of which one (phenyl cyclohexane) is common with ZLI 1275.

Keywords:

• birefringence
• dielectric
• mesogen
• order parameter
• polarizabilities

ACKNOWLEDGMENT

Thanks are due to Prof. P. Nandy, Department of Physics, Jadavpur University, and Dr. Ruma Basu for helping us with the texture studies. One of the authors (S. C.) thankfully acknowledges a University Grants Commission (UGC) Research Associateship.