Morphologies of three-phase emulsions of the ternary nonionic amphiphile/oil/water systems and their determination by electrical method.

Equations have been developed for the electrical and thermal conductivities of dispersions of two different phases of low conductivity in a third, conductive phase. These equations predict the conductivity of the dispersion from the volume fractions and conductivities of the constituent phases. Electrical conductivity measurements on dispersions of three liquid phases, i.e., three-phase emulsions, were made over a wide range of volume fractions of each dispersed phase and used to test the equations. The equations predict accurately dispersion conductivities from the measured volume fractions and conductivities of the constituent phases without any adjustable parameters. The predicted values are in excellent agreement with the measured conductivities of three-phase emulsions in the nonionic amphiphile/oil/water systems. This leads to the determination of three-phase emulsion morphologies. When the ratio Kd of the emulsion-drop conductivity to the continuous phase conductivity is O(10(-1)) <Kd <1, the electrical method yields the correct morphology. When Kd << 1, the equations predicted several morphologies, but the correct morphology can be chosen when the data are supplemented by another method such as microscopy. The electrical method, which is a combination of conductivity measurements and their fits to the equations, has been proven to be effective and reliable in determination of three-phase dispersion morphologies.