STUDY OF THE DYNAMICS OF WATER/AEROSOL OT/N-HEPTANE SYSTEM BY DIELECTRIC-RELAXATION MEASUREMENTS

Most of the previous dielectric studies on microemulsions and related systems have been conducted at relatively low frequencies where the dielectric response is sensitive to dynamic percolation phenomena. There is a lack of experimental studies at microwave frequencies where water plays a central role in dielectric relaxation. In this paper the dielectric complex permittivity of water/Aerosol OT/n-heptane microemulsions has been measured by a frequency domain coaxial technique in the range 0.02-20 GHz as a function of molar ratio W = [water]/[AOT] at low volume fraction of the dispersed phase (phi = 0.1 and phi = 0.2). The data show two dielectric dispersions: The first located in the 100 MHz frequency region and the second at frequencies higher than 20 GHz. The evolution of the dielectric parameters of these relaxations has been studied as a function of the molar ratio W in the range 0 < W < 28.