Dynamics and interactions in aqueous polyvinylpyrrolidone (PVP K-30): An approach using dielectric relaxation spectroscopy
IR@NISCAIR: CSIR-NISCAIR, New Delhi - ONLINE PERIODICALS REPOSITORY (NOPR)
View Archive Info| Field | Value | |
| Title |
Dynamics and interactions in aqueous polyvinylpyrrolidone (PVP K-30): An approach using dielectric relaxation spectroscopy
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| Creator |
Sarode, Arvind V
Kumbharkhane, Ashok C Mehrotra, Suresh C |
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| Subject |
Polyvinylepyrrolidone
Dielectric relaxation Hydration number Dipole moment Thermodynamic parameter |
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| Description |
335-340
Concentration dependent dielectric relaxation of polyvinylpyrrolidone (PVP) [C<sub>6</sub>H<sub>9</sub>NO)<sub>n</sub> K-30 having molecular weight 40000 gmol<sup>-1</sup> has been studied at temperature 298.15 K using time domain reflectometry (TDR) in the frequency range 10 MHz to 30 GHz. The frequency dependence of the complex dielectric permittivity has been analyzed by the Havriliak-Negami expression. For PVP-water system, the concentration range covers PVP molar concentration of 0.00017≤<em>c</em>/M≤0.00067. Two relaxation processes have been detected for aqueous PVP, therefore, two Debye relaxation model was required for consistent description of the complex dielectric permittivity spectra, ε*(ν). The low frequency relaxation process called β-relaxation has been associated with the rotational motion of PVP molecules in the aqueous medium while the high frequency relaxation called γ-relaxation has been associated with the rotation of free water molecules. The low frequency dispersion of relaxation time τ<sub>β</sub> ~ 980 ps attributed to rotational motion of PVP, exhibits a linearly increasing amplitude, ∆ε<sub>β </sub>(<em>c</em>) from which an effective dipole moment of μ<sub>eff</sub> = 3.43 D was deduced for the PVP molecules. The value is in close agreement with the dipole moment 3.85 D for PVP as reported in literature. The values of dipole moments were used to estimate concentration dependence hydration number (Nhyd) of PVP. Dielectric parameters have been corroborated by the parameters: the molar entropy, and molar free energy for both low and high relaxation processes. |
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| Date |
2018-04-16T09:09:34Z
2018-04-16T09:09:34Z 2018-04 |
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| Type |
Article
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| Identifier |
0975-0959 (Online); 0301-1208 (Print)
http://nopr.niscair.res.in/handle/123456789/44195 |
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| Language |
en_US
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| Rights |
<img src='http://nopr.niscair.res.in/image/cc-license-sml.png'> <a href='http://creativecommons.org/licenses/by-nc-nd/2.5/in' target='_blank'>CC Attribution-Noncommercial-No Derivative Works 2.5 India</a>
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| Publisher |
NISCAIR-CSIR, India
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| Source |
IJPAP Vol.56(04) [April 2018]
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