Complex dielectric properties of macroemulsions in the microwave region

Abstract

The complex dielectric properties of macroemulsions in the microwave frequency region were analyzed using interaction potential models and effective medium theories. The computations confirmed our earlier experimental finding (J. P. Perl, H. E. Bussey, and D. T. Wasan, J. Colloid Interface Sci. 108, 528, 1985) that a single value of the dielectric modulus could be to simultaneously determine emulsion type and estimate water content. Cole—Cole's modified Debye relaxation equations were used to obtain the pure component dielectric properties as a function of frequency. These values were incorporated into emulsion dielectric models to obtain permitivity and loss factor as a function of frequency. The computed results are in agreement with experimental results obtained from time domain dielectrometry. The computations showed that the technique can be used to determine emulsion characteristics over a wide frequency range 10 8–10 11 Hz. in the microwave region, far removed from the effects of interfacial polarization. The computed and experimental values of the dielectric moduli of emulsions were shown to be frequency invariant in the microwave region.