Effects of salinity on the electrical conductivity of a water-in-oil microemulsion

Abstract

The low-frequency electrical conductivity of water-in-oil microemulsions in presence of NaCl electrolyte solution has been measured in the temperature range from −15 to 60°C, for different volume fractions of the surfactant + water phase, in the interval from Φ = 0.1 to Φ = 0.8. The effects induced by the presence of the added salt, concerning the phase diagram in the (Φ − T) plane and the conductivity regimes far and close to the percolation, are discussed on the basis of the Eicke-Hall theory and a new approach to the conductometric behavior of microemulsions recently developed, which gives a more detailed and accurate description of the percolation characteristics.