The influence of temperature upon the dielectric behaviour of water-in-hexadecane microemulsions

Abstract

The dielectric behaviour of water-in-hexadecane microemulsions (potassium oleate being the surfactant and hexanol the cosurfactant) has been investigated for different values of the mass fraction of water p between 20 degrees C and 45 degrees C and over the frequency range 100 kHz-2000 MHz. A dielectric relaxation of the Cole-Cole type was found. Upon increasing the temperature T, the low-frequency relative permittivity epsilon 1 passes through a maximum whilst the critical frequency nu c passes through a minimum. The maximum of the epsilon 1 versus T curve decreases and shifts towards higher temperatures upon decreasing p.