Abstract
Behavior of the electric double layer around each particle was evaluated by experimental studies. An electric field was applied to each test liquid by a parallel electrodes ; one side of one of the electrodes was covered with dielectric thin film. Surface potential of the dielectric thin film was measured after certain periods of application of driving voltage. A rapid raise of the electric potential, which was almost the same value as the applied voltage, was measured at the hydrocarbon liquid mixed with metal soap with fine particles. On the other hand, such a quick rise of the surface potential was not observed at any other liquid : a hydrocarbon liquid, a hydrocarbon liquid mixed with the fine particles, and a hydrocarbon liquid mixed with the metal soap. This result means that the electric charge of the particles are probably brought by the ions derived not from the water content in the liquid but form the metal soap. The experimental results also indicate that the electric double layer was destroyed, when the driving voltage applied, and counter ions in the outer layer migrated to the opposite direction that of the particles.
