Dielectric relaxation behavior of ternary systems of water/toluene/Triton X-100: the effects of water and oil contents on microemulsion structure

Abstract

Dielectric relaxation studies were conducted on the ternary systems of the nonionic surfactant Triton X-100 (a nonionic surfactant with a polyoxyethylene chain)/toluene/water in the frequency range from 40 Hz to 110 MHz. The contents of water and toluene were varied separately while the ratios of the other two components were fixed. Remarkable dielectric relaxations were observed around 1 MHz and dielectric intensity shows different variation with the increase of the contents of water or toluene. Dielectric parameters were obtained by fitting the data using the Cole–Cole equation with one dispersion term. The reverse micelles, water-in-oil, and oil-in-water micro-regions of the microemulsions were identified by the dependence of conductivity of the dispersed phase and continuous phase on the contents of water or toluene. Hanai theory and the corresponding analysis method were used to calculate the phase parameters of the constituent phases. The analysis results suggest that the dielectric relaxation probably arises from the interfacial polarization.