T. Skodvin et al., WATER-IN-CRUDE-OIL EMULSIONS FROM THE NORWEGIAN CONTINENTAL-SHELF .9.A DIELECTRIC SPECTROSCOPIC CHARACTERIZATION OF AUTHENTIC AS WELL AS MODEL SYSTEMS, Journal of colloid and interface science, 166(1), 1994, pp. 43-50
Properties of water-in-crude oil emulsions and model systems stabilize
d by interfacially active crude oil fractions or tetraoxyethylene nony
lphenyl ether were analyzed using time domain dielectric spectroscopy.
The amount of dispersed aqueous phase containing 5% NaCl varied from
10 to 50% by volume. The dielectric spectra were fitted to a Debye fun
ction. It was found that models based on heterogeneous mixture models
could not explain the static permittivities found without a slight flo
cculation. In order to interpret the whole dielectric spectrum the Bon
ed-Peyrelasse equation was numerically solved for 80 frequencies betwe
en 20 MHz and 5 GHz. A Debye function was fitted to these theoretical
spectra and corresponding relaxation times were solved. The shape fact
ors (A) obtained show the necessity of a flocculation (axial ratios 1:
10) at lower water concentrations while other more symmetrical structu
res occur at higher water contents. (C) 1994 Academic Press, Inc.