Electrical conductivity of dispersions: from dry foams to dilute suspensions

Abstract

We present new data for the electrical conductivity of foams in which the liquid fractionranges from two to seventy per cent. We compare with a comprehensive collection of priordata, and we model all results with simple empirical formulae. We achieve a unifieddescription that applies equally to dry foams and emulsions, where the droplets are highlycompressed, as well as to dilute suspensions of spherical particles, where the particleseparation is large. In the former limit, Lemlich’s result is recovered; in the latter limit,Maxwell’s result is recovered.