Electrical conductivity of polyaphrons (biliquid foams)

Abstract

Polyaphrons (biliquid foams) are dispersions which consist of a continuous aqueous phase and a dispersed oil phase. Electrical conductivity measurements of many polyaphrons over a range of varying oil phase volume to aqueous phase volume ratio (PVR) indicate that the path of electricity through polyaphrons is independent of the nature of oil phase and aqueous phase surfactant, oil phase surfactant concentration, the nature of oil phase components, and the type of electrolyte added to aqueous phase to enhance electrical signal. Graphs of relative electrical conductivity ratios (conductivity of polyaphron to that of aqueous phase) versus the inverse of PVR are presented. These graphs suggest characterization of polyaphrons by the identification of (1) a proportionality coefficient at high PVR, and (2) a point labelled Transition PVR associated with departure from linearity as PVR decreases. Departure from linearity occurs as geometric changes occur within polyaphron structure: spherical units called aphrons close pack until distorted polyhe~ral shapes result. Graphical results of electrical conductivity measurements of polyaphrons show better agreement with Bruggeman's Equation than with Maxwell Equation or Meredith-Tobias Equation over the entire range of dispersed phase volumetric fraction.