Low frequency dielectric relaxation processes and ionic conductivity of montmorillonite clay nanoparticles colloidal suspension in poly(vinyl pyrrolidone)−ethylene glycol blends

Sengwa, R. J.; Choudhary, Shobhna; Sankhla, Sonu

doi:10.3144/expresspolymlett.2008.93

Cited by 87 publications

(54 citation statements)

References 49 publications

(99 reference statements)

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“…The complex impedance plots at different temperatures which are shown in Figure 8, are strongly support the above explanation for the increase of M′ and M″. The complex impedance plots (Z″ vs. Z′) are commonly used to separate the bulk material (depressed semicircle) and the electrode surface polarization phenomena (tilted spike) [30]. The electrode polarization phenomena (tilted spike) occurs due to formation of electric double layer (EDL) capacitances by the free charges build up at the interface between the electrolyte and the electrode surfaces in plane geometry [30,22].…”

Section: Argand Plots Analysissupporting

confidence: 71%

“…The complex impedance plots (Z″ vs. Z′) are commonly used to separate the bulk material (depressed semicircle) and the electrode surface polarization phenomena (tilted spike) [30]. The electrode polarization phenomena (tilted spike) occurs due to formation of electric double layer (EDL) capacitances by the free charges build up at the interface between the electrolyte and the electrode surfaces in plane geometry [30,22]. The appearance of second semicircle at different temperatures can be attributed to silver nanoparticles that acts as grain boundaries in the present system ( Figure 8).…”

Section: Argand Plots Analysismentioning

confidence: 99%

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Influence of silver ion reduction on electrical modulus parameters of solid polymer electrolyte based on chitosan-silver triflate electrolyte membrane

Aziz¹,

Abidin²,

Arof³

2010

Express Polym. Lett.

186

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Abstract. The electric modulus properties of solid polymer electrolyte based on chitosan: AgCF3SO3 from 303 to 393 K have been investigated by using impedance spectroscopy. The shift of the M″ peak spectra with frequeny depends on the dissociation and association of ions. The lowest conductivity relaxation time τσ, was found for the sample with the highest conductivity. The real part of electrical modulus shows that the material is highly capacitive. The asymmetric peak of the imaginary part of electric modulus M″, predicts a non Debye type relaxation. The distribution of relaxation times was indicated by a deformed arc form of Argand plot. The increase of M′ and M″ values above 358 K can be attributed to the transformation of silver ions to silver nanoparticles. The complex impedance plots and ultraviolet-visible (UV-vis) absorption spectroscopy indicate the temperature dependent of silver nanoparticles in chitosan-silver triflate solid electrolyte. The formation of silver nanoparticles was confirmed by transmission electron microscopy (TEM). The scaling behavior of M″ spectra shows that the dynamical relaxation processes is temperature independent for aparticular composition. The β exponent value indicate that the conductivity relaxation is highly non exponential.

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Section: Argand Plots Analysissupporting

confidence: 71%

Section: Argand Plots Analysismentioning

confidence: 99%

Influence of silver ion reduction on electrical modulus parameters of solid polymer electrolyte based on chitosan-silver triflate electrolyte membrane

Aziz¹,

Abidin²,

Arof³

2010

Express Polym. Lett.

186

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“…Prior to the sample measurements, the open circuit calibration of the cell was performed to eliminate the effect of stray capacitance. The details of the evaluation of complex dielectric function ε * (ω) = ε′ -jε″, complex alternating current (ac) electrical conductivity σ * (ω) = σ′ + jσ″, complex electric modulus M * (ω) = M′ + jM″and complex impedance Z * (ω) = Z′ -jZ″ of the solid PCNs films are described by us elsewhere [29][30][31]34]. Figure 1a shows that the real part ε′ of the complex dielectric function of PVA-MMT clay nanocomposites decreases with the increase in frequency of applied alternating electric field from 20 Hz to 1 MHz, which confirms the dielectric dispersion in these materials.…”

Section: Measurementsmentioning

confidence: 99%

“…The complex dielectric function, alternating current (ac) electrical conductivity, impedance properties and electric modulus spectra of the PVA-MMT clay nanocomposite films were investigated over the frequency range 20 Hz to 1 MHz. An attempt is made to correlate the values of various dielectric parameters with structural behaviour of these nanocomposites materials to establish the use of dielectric relaxation spectroscopy as diagnostic tool for the development of on-line testing and monitoring of the nanocomposite formation in PCNs materials [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33].…”

Section: Introductionmentioning

confidence: 99%

Investigation of correlation between dielectric parameters and nanostructures in aqueous solution grown poly(vinyl alcohol)-montmorillonite clay nanocomposites by dielectric relaxation spectroscopy

Sengwa¹,

Choudhary²

2010

Express Polym. Lett.

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Abstract. Poly(vinyl alcohol) (PVA)-montmorillonite (MMT) clay nanocomposite films up to 10 wt% clay concentration were synthesized by aqueous solution grown technique. The relative complex dielectric function, alternating current electrical conductivity, electric modulus and impedance properties of these organic-inorganic nanocomposites were investigated in the frequency range from 20 Hz to 1 MHz at ambient temperature. The PVA-MMT clay nanocomposite films show a large decrease in the real part and loss of relative dielectric function at 1 wt% MMT clay loading compared to pure PVA film and anomalous behaviour is observed with further increase of clay concentration in PVA matrix. Two dielectric relaxation processes were observed in these nanocomposites; a high frequency relaxation associated with PVA segmental motion and a low frequency relaxation resulting from PVA/dispersed MMT clay interfacial polarization (Maxwell-Wagner relaxation). Dielectric relaxation times corresponding to these processes were determined by fitting dc conductivity corrected complex dielectric function data to the Havriliak-Negami expression. A correlation between change in dielectric relaxation strength, relaxation time and hindrance to the PVA-chain dynamics with the degree of exfoliated structures of dispersed nanoscale MMT clay filler in the PVA matrix were explored. Results confirm the application of dielectric relaxation spectroscopy as a potential tool in the confirmation of nanocomposite formation and their structure characterization.

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“…A complex dielectric modulus, M * (equations (6)- (8)) is used to predict dielectric relaxation when electric displacement remains constant due to space charge polarization [32,33]. Figures 5(a), (b) illustrate the frequency dependence of the real (M′) and imaginary part (M″) of the nanocomposites.…”

Section: Materials Characterizationmentioning

confidence: 99%

The tunable permittivity of multi-walled carbon nanotubes/silver nanoparticles reinforced polyvinyl alcohol (PVA) nanocomposites at low frequency

Yusof

Wong

et al. 2018

Mater. Res. Express

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This paper is about tailoring high permittivity of multi-walled carbon nanotubes/silver nanoparticles (MWNT-AgNP) filled polyvinyl alcohol (PVA) nanocomposites at low frequency. PVA/MWNTAgNP nanocomposites were synthesized via solution-casting technique at low MWNT content with different loading of AgNP. The nanocomposites showed a significant increment in ac conductivity, σ ac , and dielectric permittivity, ε′ by two orders of magnitude as compared to pure PVA. The maximum ε′ value was achieved about 600 at 1.0 wt% of AgNP due to the increased charge carriers density and high interfacial polarization within the nanocomposites. The relaxation frequency was shifted towards a higher value with the increased of AgNP content while the relaxation time was decreased by 40%. Field emission scanning electron microscopy (FESEM) images showed the enhanced distribution of MWNT in the presence of AgNP to provide conductive pathways in the matrix. This was confirmed by energy-dispersive x-ray (EDX) analysis and ultraviolet-visible (UV-vis) spectroscopy. As a result, PVA/MWNT-AgNP nanocomposites have great potential for electrical applications such as cable accessories, high charge-storage capacitor and electromagnetic interference shielding materials.

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Low frequency dielectric relaxation processes and ionic conductivity of montmorillonite clay nanoparticles colloidal suspension in poly(vinyl pyrrolidone)−ethylene glycol blends

Cited by 87 publications

References 49 publications

Influence of silver ion reduction on electrical modulus parameters of solid polymer electrolyte based on chitosan-silver triflate electrolyte membrane

Influence of silver ion reduction on electrical modulus parameters of solid polymer electrolyte based on chitosan-silver triflate electrolyte membrane

Investigation of correlation between dielectric parameters and nanostructures in aqueous solution grown poly(vinyl alcohol)-montmorillonite clay nanocomposites by dielectric relaxation spectroscopy

The tunable permittivity of multi-walled carbon nanotubes/silver nanoparticles reinforced polyvinyl alcohol (PVA) nanocomposites at low frequency

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