Analysis of complex dielectric spectra. I. One-dimensional derivative techniques and three-dimensional modelling

Wübbenhorst, Michael; Turnhout, J. van

doi:10.1016/s0022-3093(02)01086-4

Cited by 531 publications

(511 citation statements)

References 16 publications

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“…A convenient technique to eliminate this contribution from ε′′(f) is based on the calculation of the derivative of the real part of the dielectric function, which yields an expression for the dielectric loss free from the contribution of the ohmic conduction (eq 1). 31 The approximation ε deriv ′′ ≈ ε′′ holds for broad peaks like those of the dynamic glass transition or secondary relaxations. Peaks in spectra obtained via eq 1 are markedly narrower than the measured ones, leading to a better resolution of the overlapping molecular processes.…”

Section: Resultsmentioning

confidence: 99%

“…31 The expression for ∂ε HN ′ /∂ ln ω reads with The temperature dependence of ε deriv ′′ (10 kHz) upon heating and cooling is given in Figure 5. This quantity is sensitive to changes in the friction of dipoles at the molecular scale and consequently can be used to monitor structural rearrangements occurring during a phase transition.…”

Section: Resultsmentioning

confidence: 99%

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Dynamics of the Crystal to Plastic Crystal Transition in the Hydrogen Bonded N-Isopropylpropionamide

et al. 2010

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N-Isopropylpropionamide (NiPPA), which can self-associate via hydrogen bonds, was found to undergo a solid-solid transition as identified by DSC and X-ray diffraction. Below the melting temperature of 51 °C NIPPA adopts a plastic crystalline state with a tetragonal unit cell until it transforms into an ordered crystal with a monoclinic structure at temperatures e10 °C. Dielectric spectroscopy was used to characterize the dynamics of the system, determining the activation parameters for the plastic to crystalline phase transition. The activation enthalpy is relatively high, as expected for a system that involves hydrogen bonds. However, most of the activation energy as the plastic phase assumes a more crystalline state is due to the activation entropy, suggesting that the increased cooperativity observed in the relaxation processes is due to a steric locking of the molecules.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Dynamics of the Crystal to Plastic Crystal Transition in the Hydrogen Bonded N-Isopropylpropionamide

et al. 2010

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“…18 An additional advantage with using the real part is that pure conductivity is not contributing to the spectra. 18 This obviously improves the chances to observe low frequency processes that are covered by the conductivity contribution. …”

Section: Methodsmentioning

confidence: 99%

Slow Debye-type peak observed in the dielectric response of polyalcohols

Bergman

Jansson

Swenson

2010

The Journal of Chemical Physics

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Dielectric relaxation spectroscopy of glass forming liquids normally exhibits a relaxation scenario that seems to be surprisingly general. However, the relaxation dynamics is more complicated for hydrogen bonded liquids. For instance, the dielectric response of monoalcohols is dominated by a mysterious Debye-like process at lower frequencies than the structural ␣-relaxation that is normally dominating the spectra of glass formers. For polyalcohols this process has been thought to be absent or possibly obscured by a strong contribution from conductivity and polarization effects at low frequencies. We here show that the Debye-like process, although much less prominent, is also present in the response of polyalcohols. It can be observed in the derivative of the real part of the susceptibility or directly in the imaginary part if the conductivity contribution is reduced by covering the upper electrode with a thin Teflon layer. We report on results from broadband dielectric spectroscopy studies of several polyalcohols: glycerol, xylitol, and sorbitol. The findings are discussed in relation to other experimental observations of ultraslow ͑i.e., slower than the viscosity related ␣-relaxation͒ dynamics in glass formers.

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“…One is based on the analysis of the logarithmic derivative ͑LD͒ of dielectric constant, 22,23 which is based on the following derivative: …”

Section: Calculating Dielectric Loss From Dielectric Constantmentioning

confidence: 99%

“…The dielectric theories on Maxwell-Wagner ͑MW͒ polarization relaxation [12][13][14] and counterion polarization relaxation, [15][16][17] which are the most typical relaxation mechanisms for colloidal suspensions in the radio frequency range, and can offer rich information on particle dispersion state, charge diffusion, interfacial configuration, and so on. [18][19][20][21] Data treatment methods such as the logarithmic derivative method 22,23 and numerical Kramers-Kronig transform method 24 have been developed in the past decade, which can markedly increase the accuracy of the dielectric data processing. Since many applications, such as used as catalyzer, demand that NP assemblies be in the state of colloidal suspension, DRS investigations on their colloidal suspensions may offer information about their structure in their working state, and thus are hoped to reveal the working mechanism and to further their applications.…”

Section: Introductionmentioning

confidence: 99%

Dielectric relaxation behavior of colloidal suspensions of palladium nanoparticle chains dispersed in PVP/EG solution

Chen

Zhao

Guo

et al. 2007

The Journal of Chemical Physics

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Phase separation in suspensions of colloids, polymers and nanoparticles: Role of solvent quality, physical mesh, and nonlocal entropic repulsion J. Chem. Phys. 118, 3880 (2003); 10.1063/1.1538600Reuse of AIP Publishing content is subject to the terms: https://publishing.aip.org/authors/rights-and-permissions. Dielectric measurements were carried out on colloidal suspensions of palladium nanoparticle chains dispersed in poly͑vinyl pyrrolidone͒/ethylene glycol ͑PVP/EG͒ solution with different particle volume fractions, and dielectric relaxation with relaxation time distribution and small relaxation amplitude was observed in the frequency range from 10 5 to 10 7 Hz. By means of the method based on logarithmic derivative of the dielectric constant and a numerical Kramers-Kronig transform method, two dielectric relaxations were confirmed and dielectric parameters were determined from the dielectric spectra. The dielectric parameters showed a strong dependence on the volume fraction of palladium nanoparticle chain. Through analyzing limiting conductivity at low frequency, the authors found the conductance percolation phenomenon of the suspensions, and the threshold volume fraction is about 0.18. It was concluded from analyzing the dielectric parameters that the high frequency dielectric relaxation results from interfacial polarization and the low frequency dielectric relaxation is a consequence of counterion polarization. They also found that the dispersion state of the palladium nanoparticle chain in PVP/EG solution is dependent on the particle volume fraction, and this may shed some light on a better application of this kind of materials.

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Analysis of complex dielectric spectra. I. One-dimensional derivative techniques and three-dimensional modelling

Cited by 531 publications

References 16 publications

Dynamics of the Crystal to Plastic Crystal Transition in the Hydrogen Bonded N-Isopropylpropionamide

Dynamics of the Crystal to Plastic Crystal Transition in the Hydrogen Bonded N-Isopropylpropionamide

Slow Debye-type peak observed in the dielectric response of polyalcohols

Dielectric relaxation behavior of colloidal suspensions of palladium nanoparticle chains dispersed in PVP/EG solution

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