Effect of electric field on electrical conductivity of dielectric liquids mixed with polar additives: DC conductivity.

To understand the dynamics of dielectric-liquid-based colloidal systems, the effect of electric field on conductivity of dielectric liquids must be characterized. We measured dc conductivity of dielectric liquids mixed with polar additives, including surfactants, an alcohol, and an oil-soluble salt. The conductivities of the mixtures increased with the electric field and concentration of polar additives and were also affected by temperature. Conductivity increased with electric-field strength at very similar rates, almost irrespective of the kind of mixture. A simple formula derived from Onsager theory predicted the electrical conductivity under electric field fairly well.