Frequency dependent conductivity in polymers and other disordered materials

Rehwald, W.; Kiess, H.; Binggeli, B.

doi:10.1007/bf01304219

Cited by 47 publications

(17 citation statements)

References 20 publications

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“…(c) Thermoplastic polyurethane doped with NH 4 CF 3 SO 3 (van Heumen et al, 1995). (d) Poly(methylthiophene) (Rehwald, Kiess, and Binggeli, 1987). (e) Amorphous germanium film (inset: approximate power-law exponent -here labeled s-as a function of temperature) (Long and Balkan, 1980).…”

Section: Ac Conduction In Disordered Solids: Factsmentioning

confidence: 99%

“…1(a) (Kulkarni, Lunkenheimer, and Loidl, 1998); (b) gives the master curve for the electron conducting polymer data of Fig. 1(d) (Rehwald, Kiess, and Binggeli, 1987); (c) gives master curves for data on eight different ion conducting oxide glasses (Roling, 1998). of being constant as for an exact power-law-goes to one as scaled frequency goes to infinity.…”

Section: Ac Conduction In Disordered Solids: Factsmentioning

confidence: 99%

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Universality of ac conduction in disordered solids

2000

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The striking similarity of ac conduction in quite different disordered solids is discussed in terms of experimental results, modeling, and computer simulations. After giving an overview of experiment, a macroscopic and a microscopic model are reviewed. For both models the normalized ac conductivity as a function of a suitably scaled frequency becomes independent of details of the disorder in the extreme disorder limit, i.e., when the local randomly varying mobilities cover many orders of magnitude. The two universal ac conductivities are similar, but not identical; both are examples of unusual non-power-law universalities. It is argued that ac universality reflects an underlying percolation determining dc as well as ac conductivity in the extreme disorder limit. Three analytical approximations to the universal ac conductivities are presented and compared to computer simulations. Finally, model predictions are briefly compared to experiment. CONTENTS I. Introduction 873 II. Preliminaries 873 III. Ac Conduction in Disordered Solids: Facts 874 IV. Macroscopic Model 877 A. Definition 877 B. Ac universality in the extreme disorder limit 878 V. Symmetric Hopping Model 880 A. Definition 880 B. Ac universality in the extreme disorder limit 882 VI. Cause of Universality 883 A. Role of percolation 883 B. Percolation based approximations 885 VII. Discussion 887 A. Model predictions 887 B. Models versus experiment 888 C. Outlook 888 Acknowledgments 890 References 890

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Section: Ac Conduction In Disordered Solids: Factsmentioning

confidence: 99%

Section: Ac Conduction In Disordered Solids: Factsmentioning

confidence: 99%

Universality of ac conduction in disordered solids

2000

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“…36 For example, inorganic solids, glasses, semiconductors, and polymers have been found to follow FTS. 37,38 Figures 7(a) and 7(b) display the variation of the normalized parameter M /M max for 3 wt.% GdCl 3 -and 3 wt.% ErCl 3 -doped PVDF as a function of f/f max at different temperatures. It is noted that the low-frequency and high-frequency sides of the relaxation peak are slightly different.…”

Section: Frequency Temperature Superposition (Fts)mentioning

confidence: 99%

Dielectric properties of PVDF thin films doped with 3 wt.% of RCl3 (R = Gd or Er)

2014

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The dielectric permittivity (ɛ′), electric modulus (M″), and ac conductivity (σac) of pure polyvinylidene fluoride (PVDF) and PVDF containing 3 wt.% RCl3 (R = Er or Gd) were measured. The incorporation of 3 wt.% of ErCl3 or GdCl3 within the PVDF matrix is found significantly to increase its ɛ′ and σac. All investigated samples show different relaxation processes within the studied temperature and frequency ranges. The first process is αa-relaxation, which occurs around the glass transition temperature, Tg. The second process is αc-relaxation, which is associated with the molecular motions in the crystalline region of the main polymer chain. Third is the ρ-relaxation which observed for pure PVDF at low temperatures and high frequencies. The frequency dependence of σac shows that the conduction mechanism for pure PVDF and PVDF containing 3 wt.% of RCl3 is correlated barrier hopping (CBH). The binding energy of the carriers was calculated based on the CBH model. Finally, the results obtained in this work are discussed and compared with those for 3 wt.% LaCl3-doped PVDF and similar materials.

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“…The conduc tivity of pure PAN in the frequency range below 2 × 10 4 Hz is seen to be proportional to f 0.9 . According to [13,14], this character of the frequency dependence points to a hopping charge transfer mechanism in the samples. When the measurement temperature increases, segments with σ ac ~ f 0.4 (not shown) appear in the polymer conductivity curves in the low fre quency region.…”

Section: Resultsmentioning

confidence: 95%

Frequency dependence of the electrical conductivity in Ag/PAN nanocomposites

et al. 2012

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The frequency dispersion of the electrical conductivity of silver/polyacrylonitrile nanocomposite films is studied at various temperatures and AgNO 3 contents in an initial mixture. The frequency depen dences of the nanocomposites in the range 10 3 -10 6 Hz are found to be well described by power law f 0.8 . A charge transfer mechanism responsible for the conductivity of the nanocomposites is proposed. Silver clus ters and are assumed to be present in the polymer.

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Frequency dependent conductivity in polymers and other disordered materials

Cited by 47 publications

References 20 publications

Universality of ac conduction in disordered solids

Universality of ac conduction in disordered solids

Dielectric properties of PVDF thin films doped with 3 wt.% of RCl3 (R = Gd or Er)

Frequency dependence of the electrical conductivity in Ag/PAN nanocomposites

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