Dielectric dispersion in some polymers and polyelectrolytes: A model

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Abstract
A simple model is investigated for macromolecules which exhibit a giant dielectric constant and a dispersion region at unusually low frequencies. The model postulates a hopping mechanism of carriers along the linear macromolecule. A theory iseory is developed for the dielectric behavior of the model, and its dependence on frequency and on an applied dc bias field. The model does exhibit the experimentally observed large dielectric constant, as well as very long relaxations. Although many modes with different relaxation times are found to exist, only the mode with the longest relaxation time contributes significantly to the ac conductivity at small values of dc bias. The presence of a dc bias shortens the relaxation times for all the modes. In addition, the relative importance of the mode with the longest relaxation time decreases with increasing bias. The real part of the conductivity decreases at all frequencies as the bias increases. The real part of the dielectric constant, however, decreases at low frequencies, but can increase at high frequencies as the bias increases.

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