Datensatz

Zusammenfassung

A continuum electrostatic calculation explores dielectric heterogeneity in membranes and its influence on ion sorption. The spherical shell model of Ullman is used. A transition in predicted sorption behaviour occurs as b, the mean ionic radius, becomes comparable with L, the size of dielectric domains. Since the finite size of molecules establishes a lower limit of L ˜ b, it is likely that no membrane is a strictly homogeneous dielectric from the standpoint of ion sorption. The calculation predicts that changing the dielectric domain size between 5 · 10⁻⁸ and 20 · 10⁻⁸ cm has a drastic effect on ion sorption. Objections which can arise from the very special nature of Ullman's model are discussed.