Calculation of various relaxation times and conductivity for a single dielectric relaxation process

The dielectric relaxation times τ and dipole moments μ of N-methylacetamide (NMA) mixed with N,N-dimethylformamide (DMF) in benzene solutions have been obtained using standard standing wave microwave techniques and Gopala Krishna’s single frequency (9.90 GHz) concentration variational method at 25, 30, 35, and 40 ◦C. The energy parameters (ΔHε , ΔFε , ΔSε ) for the dielectric relaxation process of mixtures with equal amounts of NMA and DMF have been calculated and compared with the corresponding energy parameters (ΔHη , ΔFη , ΔSη ) for the viscous flow. On the basis of the observations it is found that the dielectric relaxation process can be treated as a rate process like the viscous flow. Solute-solute and solute-solvent types of the molecular associations have been predicted

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Dielectric Relaxation of Binary Mixtures of Tetrahydrofuran and N-Methylformamide in Benzene Solution Using Microwave Absorption Studies

Zeitschrift für Naturforschung A ◽

10.1515/zna-2010-1-216 ◽

2010 ◽

Vol 65 (1-2) ◽

pp. 141-144 ◽

Cited By ~ 1

Author(s):

Raman Kumar ◽

Vir S. Rangra

Keyword(s):

Binary Mixture ◽

Dielectric Relaxation ◽

Relaxation Process ◽

Binary Mixtures ◽

Benzene Solution ◽

Relaxation Times ◽

Single Frequency ◽

Flow Process ◽

Dielectric Relaxation Process ◽

C 30

AbstractUsing standard standing wave microwave X-band technique and following Gopala Krishna’s single frequency (9.90 GHz) concentration variational method, the dielectric relaxation times τ and the dipole moments μ of dilute solutions of Tetrahydrofuran (THF), N-methylformamide (NMF), and THF+NMF binary mixtures in benzene solutions have been calculated at different temperatures (25°C, 30°C, 35°C, and 40°C). The energy parameters (ΔHε , ΔFε , ΔSε ) for the dielectric relaxation process for the THF+NMF binary mixture containing 30 mol% THF have been calculated at 25°C, 30°C, 35°C, and 40°C and compared with the corresponding viscosity parameters. A good agreement between the free energy of activation from these two sets of values shows that the dielectric relaxation process like the viscous flow process can be treated as a rate process. From relaxation time behaviour of THF and NMF binary mixture in benzene solution, solute-solute types of the molecular association has been proposed.

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Dielectric Relaxation Studies of Mixtures of N-Methylacetamide and Ethanol in Benzene Solutions Using Microwave Absorption Technique

Zeitschrift für Naturforschung A ◽

10.1515/zna-2007-3-415 ◽

2007 ◽

Vol 62 (3-4) ◽

pp. 213-217 ◽

Cited By ~ 1

Author(s):

Raman Kumar ◽

Vir Singh Rangra ◽

Dhani Ram Sharma ◽

Nagesh Thakur ◽

Nainjeet Singh Negi

Keyword(s):

Dielectric Relaxation ◽

Relaxation Process ◽

Binary Mixtures ◽

Benzene Solution ◽

Dipole Moments ◽

Relaxation Times ◽

Activation Parameters ◽

Single Frequency ◽

Dielectric Relaxation Process ◽

Free Energy Of Activation

Using standard standing wave microwave X-band techniques, and by following Gopala Krishna’s single frequency (9.90 GHz) concentration variational method, the dielectric relaxation times (τ) and dipole moments (μ) of binary mixtures of different molar concentrations of ethanol (EtOH) in binary mixtures of N-methylacetamide (NMA) and ethanol in benzene solutions at 25, 30, 35 and 40 ◦C have been calculated. The activation parameters (ΔHε , ΔFε , ΔSε ) for the dielectric relaxation process of binary mixtures containing 30 mol% of EtOH have been calculated at 25, 30, 35 and 40 ◦C and compared with the corresponding viscosity parameters. A good agreement between the free energy of activation from these two sets of values shows that the dielectric relaxation process, like the viscous flow, can be treated as a rate process. From relaxation time behaviour of NMA and EtOH binary mixtures in benzene solution, solute-solute and solute-solvent types of the molecular association have been predicted.

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Dielectric Relaxation Studies of Silver Nanoparticles dispersed Liquid Crystal

JOURNAL OF ADVANCES IN PHYSICS ◽

10.24297/jap.v8i3.1496 ◽

2015 ◽

Vol 8 (3) ◽

pp. 2176-2188 ◽

Cited By ~ 4

Author(s):

Keisham Nanao Singh

Keyword(s):

Activation Energy ◽

Silver Nanoparticles ◽

Liquid Crystal ◽

Dielectric Relaxation ◽

Relaxation Process ◽

Relaxation Times ◽

Low Frequency ◽

Bulk Liquid ◽

Molecular Rearrangement ◽

Relaxation Studies

This article reports on the Dielectric Relaxation Studies of two Liquid Crystalline compounds - 7O.4 and 7O.6 - doped with dodecanethiol capped Silver Nanoparticles. The liquid crystal molecules are aligned homeotropically using CTAB. The low frequency relaxation process occurring above 1 MHz is fitted to Cole-Cole formula using the software Dielectric Spectra fit. The effect of the Silver Nanoparticles on the molecular dipole dynamics are discussed in terms of the fitted relaxation times, Cole-Cole distribution parameter and activation energy. The study indicate a local molecular rearrangement of the liquid crystal molecules without affecting the order of the bulk liquid crystal molecules but these local molecules surrounding the Silver Nanoparticles do not contribute to the relaxation process in the studied frequency range. The observed effect on activation energy suggests a change in interaction between the nanoparticles/liquid crystal molecules.

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PVDF-HFP/NKBT composite dielectrics: Perovskite particles induce the appearance of an additional dielectric relaxation process in ferroelectric polymer matrix

Polymer Testing ◽

10.1016/j.polymertesting.2021.107093 ◽

2021 ◽

Vol 96 ◽

pp. 107093

Author(s):

Vera P. Pavlović ◽

Dragana Tošić ◽

Radovan Dojčilović ◽

Duško Dudić ◽

Miroslav D. Dramićanin ◽

...

Keyword(s):

Dielectric Relaxation ◽

Relaxation Process ◽

Polymer Matrix ◽

Dielectric Relaxation Process ◽

Ferroelectric Polymer

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Model for the Dielectric Relaxation Process of a Characteristic Substrate: Benzoyl(diazo)phenylmethane

Zeitschrift für Physikalische Chemie ◽

10.1524/zpch.1984.142.2.201 ◽

1984 ◽

Vol 142 (2) ◽

pp. 201-207 ◽

Cited By ~ 1

Author(s):

P. Freundlich ◽

H. A. Kołodziej ◽

S. Sorriso ◽

M. Braghetti

Keyword(s):

Dielectric Relaxation ◽

Relaxation Process ◽

Dielectric Relaxation Process

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Molecular Association of Tetramethylurea and Chlorobenzene Molecules in Microwave Frequency Range

Zeitschrift für Naturforschung A ◽

10.1515/zna-2010-1012 ◽

2010 ◽

Vol 65 (10) ◽

pp. 854-858

Author(s):

Vimal Sharma ◽

Nagesh Thakur

Keyword(s):

Relaxation Time ◽

Dielectric Relaxation ◽

Viscous Flow ◽

Relaxation Process ◽

Binary Mixtures ◽

Variation Method ◽

Dielectric Relaxation Time ◽

Flow Process ◽

Dielectric Relaxation Process ◽

Energy Parameters

The dielectric constant ε´ and dielectric loss ε´´ of the binary mixtures of tetramethylurea (TMU) and chlorobenzene (CB) have been calculated at 9.883 GHz by using standard standing microwave techniques. Gopalakrishna’s single frequency concentration variation method has been used to calculate dipole moment μ and dielectric relaxation time τ for different mole fractions of TMU in the binary mixture at different temperatures of 25 °C, 30 °C, 35 °C, and 40 °C. The variation of dielectric relaxation time with the mole fraction of TMU in the whole concentration range of the binary mixtures was found to be non-monotonic. The solute-solute and solute-solvent type of molecular associations may be proposed based upon above observations. Using Eyring rate equations the energy parameters ΔH, ΔF, and ΔS for the dielectric relaxation process and the viscous flow process have been calculated at the given temperatures. It is found from the comparison of energy parameters that, just like the viscous flow process, the dielectric relaxation process can also be treated as a rate process.

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