Dielectric relaxation studies in n-(4-octyloxy-2-hydroxybenzylidene)-4-carbethoxyaniline

Abstract

Temperature dependent dielectric spectroscopy of a newly synthesized compound N-(4-octyloxy-2-hydroxybenzylidene)-4-carbethoxyaniline, having a wide temperature range (˜70°C) Smectic A (SmA) phase has been carried out in the frequency range 100 Hz–10 MHz. Dielectric permittivity and loss in the homeotropic ( and ) and planar ( and ) alignments of the molecules have been determined. Relaxation frequencies corresponding to the rotation of the molecules about their short axes have been found to lie below 1 MHz and exhibit Arrhenius behaviour. Relaxation frequencies corresponding to the rotation of the molecules about their long axes are expected to lie above 10 MHz. Dielectric anisotropy (Δε′ =  − ) has been found to be negative throughout the range of the SmA phase.

Keywords:

• Permittivity and loss
• Dielectric relaxation
• Arrhenius plot
• Smectic A phase

Acknowledgements

Authors wish to thank Department of Science and Technology, New Delhi for providing financial assistance under a research project. Thanks are also due to Mr. A.K. Srivastava and Mr. M.B. Pandey for their help with the experiments.