The number of interfaces and the associated dielectric relaxations in heterogeneous systems

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Abstract
In heterogeneous systems composed of some phases, mobile electric charges accumulate on the boundary surfaces between the constituent phase under the electric field applied. This charge accumulation, the so-called interfacial polarization, gives rise to dielectric relaxations. By the use of several examples, it is shown theoretically as well as experimentally that the dielectric relaxations are equal to the interfaces in the number. Typical examples of diphase systems are (i) a series combination of a polyethylene film and an aqueous solution, and (ii) water-in-oil emulsions. These systems contain one kind of interfaces, showing one dielectric relaxation. Practical examples of triphase systems are (i) a composite system of a Teflon film sandwiched between two aqueous solutions, and (ii) polystyrene microcapsules. These systems contain two kinds of interfaces, showing two dielectric relaxations. A pentaphase system composed of shell-spheres are discussed theoretically, showing four dielectric relaxations in accordance with four kinds of the interfaces.