Dielectric relaxation spectroscopy of aqueous solutions of diclofenac potassium over the frequency range of 20 Hz to 2 MHz at 303.15 K temperature

2018 ◽  
Author(s):  
J. B. Karakthala ◽  
H. P. Vankar ◽  
V. A. Rana
Keyword(s):  
Aqueous Solutions ◽  
Dielectric Relaxation ◽  
Dielectric Relaxation Spectroscopy ◽  
Frequency Range

High Frequency Dielectric Response of the Ionic Liquid N-Methyl-N-ethylpyrrolidinium Dicyanamide

2007 ◽  
Vol 60 (1) ◽  
pp. 6 ◽  
Author(s):  
Simon Schrödle ◽  
Gary Annat ◽  
Douglas R. MacFarlane ◽  
Maria Forsyth ◽  
Richard Buchner ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Dielectric Loss ◽  
Dielectric Relaxation ◽  
High Frequency ◽  
Dielectric Response ◽  
Room Temperature ◽  
Room Temperature Ionic Liquid ◽  
Dielectric Relaxation Spectroscopy ◽  
Frequency Range ◽  
Fast Rotation

A study of the room-temperature ionic liquid N-methyl-N-ethylpyrrolidinium dicyanamide by dielectric relaxation spectroscopy over the frequency range 0.2 GHz ≤ ν ≤ 89 GHz has revealed that, in addition to the already known lower frequency processes, there is a broad featureless dielectric loss at higher frequencies. The latter is probably due to the translational (oscillatory) motions of the dipolar ions of the IL relative to each other, with additional contributions from their fast rotation.

Study of the Molecular Mobility of Polysaccharide Solid Thin Layers by Dielectric Relaxation Spectroscopy

1997 ◽  
Vol 500 ◽  
Author(s):  
K. Liedermann ◽  
L. Lapčík ◽  
S. Desmedt
Keyword(s):  
Dielectric Relaxation ◽  
Low Frequency ◽  
Thin Layers ◽  
Side Chain ◽  
Relaxation Processes ◽  
Dielectric Relaxation Spectroscopy ◽  
Frequency Range ◽  
Polar Groups ◽  
Calculated Activation Energy ◽  
Β Relaxation

ABSTRACTTemperature dependence of measured dielectric relaxation spectra (DRS) in the frequency range 20 Hz - 1 MHz of hydroxyethylcellulose (HEC) are in the temperature range 100 – 350 K. of Arrhenius character with one relaxation process at 150 – 250 K. This process reflects most probably β-relaxation of the side chain groups. Calculated activation energy of this process was 5730 kJ/mole. Four types of polysaccharides were studied at 293 K temperature: hyaluronic acid (HA), chondroitin sulfate (CHS), HEC and carboxymethylcellulose (CMC), in the low-frequency range 10−5 - 100 Hz. Measured dielectric spectra were interpreted as sum of one A.C. conductivity process and of up to two relaxation processes. The relaxation processes were described by means of the Havriliak-Negami formula and their parameters were related to the molecular structure of the polymers. The low value of a in CHS is related to its strong coupling due to the presence of two polar groups in its monomeric unit, whereas low values of α × β are interpreted as being due to the strong steric hindrances caused by long pendants present in HEC.

Effect of grafting density on conformation of poly(acrylic acid) in solution by dielectric spectroscopy

Soft Matter ◽  
2018 ◽  
Vol 14 (35) ◽  
pp. 7190-7203 ◽  
Author(s):  
Xinlu Zhou ◽  
Kongshuang Zhao
Keyword(s):  
Acrylic Acid ◽  
Ethylene Oxide ◽  
Dielectric Relaxation ◽  
Dielectric Spectroscopy ◽  
Dielectric Relaxation Spectroscopy ◽  
Frequency Range ◽  
Grafting Density ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Poly Acrylic Acid

The effect of grafting density of poly(ethylene oxide) and dodecyl groups on the conformation of poly(acrylic acid) in solution was clarified by dielectric relaxation spectroscopy over a frequency range from 40 Hz to 110 MHz.

Urea hydration from dielectric relaxation spectroscopy: old findings confirmed, new insights gained

2016 ◽  
Vol 18 (4) ◽  
pp. 2597-2607 ◽  
Author(s):  
Vira Agieienko ◽  
Richard Buchner
Keyword(s):  
Aqueous Solutions ◽  
Dielectric Relaxation ◽  
Rotational Relaxation ◽  
Water Molecules ◽  
Dielectric Relaxation Spectroscopy

In aqueous solutions urea significantly impedes rotational relaxation of 1–2 water molecules per solute.

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