The understanding of underlying physical principles governing colloidal behavior in low dielectric liquids is of fundamental interest. A model colloidal system, which consists of monodispersed, –CN terminated, silica particles in di-2-ethylhexylsulfosuccinate (AOT) and hydrocarbon fluids, was chosen to study electrophoresis of charged particles over a wide range of AOT concentrations and applied fields, up to 1.0 V/micron. These particles charge negatively in AOT/Isopar solutions. We use the electrophoretic light scattering technique to determine that particle mobilities increase with applied electric field and level off for fields larger than 0.5 V/micron, independently of AOT concentration for concentrations larger than 1 mM. At high electric fields, where the mobility is field independent, all the dispersions converge to a single value of the mobility. A physical model is proposed to explain the experimental results. The model parameters are correlated with those extracted from adsorption isotherms of AOT/silica particles. This method of characterization of the dispersions and their electrophoretic behavior provides a deep understanding of the parameters that control charging, and is most relevant for industrial applications such as liquid ink printing and electrophoretic display devices.
Faguang Jin, H. Ted Davis, D. Fennell Evans, R. Enrique Viturro, "Electrophoretic Behavior in Model Colloidal Systems" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP14), 1998, pp 206 - 209, https://doi.org/10.2352/ISSN.2169-4451.1998.14.1.art00051_1