Thermodynamical scaling of the low frequency relaxation time in liquid crystalline phases

Abstract Dielectric relaxation studies of 4-n-octyl-4'-cyanobiphenyl (8 CB) were performed in the pressure range 0.1 -120 MPa, the frequency range 1 kHz -13 MHz and the temperature range 295-331 K. The dielectric behaviour of 8C B in the nematic phase is similar to that of 5 CB, 6 CB and 7 CB. In particular, the activation enthalpy decreases with increasing pressure and the activation volume decreases with increasing temperature in the nematic phase. In the smectic A phase of 8 CB both these parameters are markedly lower and show opposite pressure and temperature dependencies. We tentatively interpret these effects as a result of breaking of the dipole-dipole correlations which manifests itself differently in these liquid crystalline phases.

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Tracer diffusion in perfectly aligned liquid crystalline phases Kinetic theory and molecular dynamics simulations

Molecular Physics ◽

10.1080/00268979709482789 ◽

1997 ◽

Vol 91 (6) ◽

pp. 993-1003 ◽

Cited By ~ 1

Author(s):

ANJALI KHARE ◽

DAVID KOFKE ◽

GLENN EVANS

Keyword(s):

Molecular Dynamics ◽

Kinetic Theory ◽

Molecular Dynamics Simulations ◽

Liquid Crystalline ◽

Tracer Diffusion ◽

Crystalline Phases ◽

Liquid Crystalline Phases ◽

Dynamics Simulations

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Integration of electro-active π-conjugated units in nanosegregated liquid-crystalline phases

Polymer Journal ◽

10.1038/pj.2016.91 ◽

2016 ◽

Vol 49 (1) ◽

pp. 75-83 ◽

Cited By ~ 11

Author(s):

Masahiro Funahashi

Keyword(s):

Liquid Crystalline ◽

Crystalline Phases ◽

Liquid Crystalline Phases

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Investigating the dielectric properties and low-frequency relaxation process of TlGaSe2 crystals

Modern Physics Letters B ◽

10.1142/s0217984917501342 ◽

2017 ◽

Vol 31 (12) ◽

pp. 1750134 ◽

Cited By ~ 1

Author(s):

Oktay Samadov ◽

Oktay Alakbarov ◽

Arzu Najafov ◽

Samir Samadov ◽

Nizami Mehdiyev ◽

...

Keyword(s):

Electrical Conductivity ◽

Relaxation Time ◽

Constant Electric Field ◽

Low Frequency ◽

Constant Field ◽

Impedance Spectra ◽

Ionic Contribution ◽

Frequency Relaxation ◽

Average Relaxation Time ◽

Diagram Analysis

The dielectric and impedance spectra of TlGaSe2 crystals have been studied at temperatures in the 100–500 K range in the alternating current (AC [Formula: see text]1 V). It has been shown that the conductivity of TlGaSe2 crystals is mainly an ionic characteristic at temperatures above 400 K. The well-defined peak at the frequency dependence of the imaginary part of impedance [Formula: see text] is observed in the 215–500 K temperature range. In a constant field, there occurs a significant decrease in electrical conductivity [Formula: see text] in due course. The ionic contribution to conductivity (76% at [Formula: see text]) has been estimated from a kinetic change in electrical conductivity [Formula: see text] under the influence of a constant electric field. The diagram analysis in a complex plane [Formula: see text] has been conducted by applying the method of an equivalent circuit of the substation. It has been determined that the average relaxation time of the electric module of the sample is [Formula: see text].

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