VELOCITY OF THE MARANGONI CONVECTION AND THE ELECTRIC-POTENTIAL IN A WATER-OIL-WATER INTERFACE SYSTEM

The velocity of the Marangoni convection and the electric potential in a water-oil-water interface system were measured simultaneously. The velocity changes periodically; it was low at first and then increased rapidly to reach to a maximum before abruptly decreasing. The burst-like wave of the electric potential oscillation, which represents the change in the concentration of the surfactant on the interface, was found to occur when the velocity reached its maximum. This result shows that the Marangoni convection is strongly coupled with the accumulation process through the transfer of the surfactant from bulk to the interface by the convection.