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Dielectric anisotropy and relaxation studies of the homologous series of N-(4-n-alkyloxy-2-hydroxy-benzylidene)-4-carbethoxyaniline

Dhar, R and Gupta, Meenal and Agrawal, VK and Singh, MK (2008) Dielectric anisotropy and relaxation studies of the homologous series of N-(4-n-alkyloxy-2-hydroxy-benzylidene)-4-carbethoxyaniline. In: Specialized Colloque AMPERE and AvH Workshop on Advanced Materials as Studied by Spectroscopic and Diffraction Techniques, SEP 16-21, 2006, Vilnius, pp. 341-359.

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Dielectric properties of the homologous series of newly synthesized nonchiral compounds N-(4-n-alkyloxy-2-hydroxy-benzylidene)-4-carbethoxyaniline, (n = 6, 8, 10, 12) having wide temperature range (∼60°C) smectic A (SmA) phase, have been studied by the impedance spectroscopy in the frequency range of 100 Hz to 1 MHz. Measurements have been carried out for two principal alignments (planar as well as homeotropic) of the SmA phase. Dielectric anisotropy (Δε' = ε'∥ - ε'⊥) for all the members of the series has been found to be negative for the whole temperature range of SmA phase. Magnitude of the dielectric anisotropy (|Δε'|) has been found to decrease with the number of alkyl chains. Relaxation frequencies corresponding to the rotation of the individual molecules about their short axes, lie below 1 MHz and obey the Arrhenius law by which activation energies have been determined. However, the relaxation frequencies corresponding to the rotation of the molecules about their short axes apparently lie above 10 MHz.

Item Type: Conference Paper
Publication: Phase Transitions: A Multinational Journal
Publisher: Taylor and Francis Group
Additional Information: Copyright of this article belongs to Taylor and Francis Group.
Keywords: Dielectric spectroscopy;Dielectric relaxation;Smectic A phase;Molecular relaxation modes;Arrhenius behavior;Activation enthalpy.
Department/Centre: Division of Chemical Sciences > Organic Chemistry
Date Deposited: 11 Mar 2010 09:17
Last Modified: 11 Mar 2010 09:17
URI: http://eprints.iisc.ac.in/id/eprint/26111

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