Le comportement diélectrique des solutions diluées de polyélectrolytes

Abstract

Dielectric constants of aqueous solutions of polyacrylic acid, partially or totally neutralised by sodium hydroxide, and of sodium, lithium and baryum polymethacrylates, were measured at various frequencies, ranging from 10 to 500 kilocycles. Polymer concentration was varied from 0.1 to 10 millimoles of monomer per liter. The degree of polymerisation was varied from circa 300 to 3,500. All dispersion curves had an inflexion point for frequencies of approximately 100 kilocycles, so that the relaxation times were of the order of one microsecond. It was hardly influenced by the degree of neutralisation, by the polymer concentration or by the molecular weight. The dielectric increment, for a given frequency, increased with the degree of neutralisation, rising sharply until α reached 0.5, rather slowly for higher degrees of neutralisation. The dielectric increment was not proportional to the polymer concentration. It was considerably lower for the salt of a divalent cation, baryum, than for the lithium and sodium salts. The increment was slightly larger for the more mobile sodium than for the lithium polymethacrylate. The degree of polymerisation was practically without influence on the dielectric increment. All the observed facts point to an interpretation attributing the dielectric properties of dilute solutions of polyelectrolytes to relaxation phenomenon in the ionic atmospheres surrounding the charges localised along the polyion. Copyright © 1955 Wiley‐VCH Verlag GmbH & Co. KGaA, WeinheimSCOPUS: ar.jinfo:eu-repo/semantics/publishe