Dielectric Properties of Dextran Gel Sephadex G-25 Dispersed in Aqueous Phases

Abstract

Dielectric relaxations were observed in beds of dextran gel beads preconditioned with different salt solutions and subsequently dispersed in deionized water in a frequency range of 10 kHz to 1 MHz. The relative permittivities and electrical conductivities of the gel beads were evaluated from the observed relaxations using the theory of interfacial polarization. The relative permittivities remained the same irrespective of the ion species in the salt solutions used for preconditioning, while the conductivities had values characteristic of the cation species in the respective salt solutions. A similar analysis was also carried out on a series of specimens with different concentrations of KCl in a continuous medium. The conductivity of the gel beads increased with the KCl concentration as expected from the theory of Donnan equilibrium.