A macroscopic interface self-motion appearing on an oil/water liquid membrane was clearly observed. The oil phase was a mixture solution containing nitrobenzene, picric acid and ethanol, whereas the aqueous phase was a solution of CTAB (cetyltrimethylammonium bromide). The interface displayed different types of motion, such as random, wave-like motion and teeterboard-like motions, which were affected by experimental conditions like concentration of reactants and geometry of the reaction vessel. A possible mechanism to explain these motions was also proposed.
self-motion; liquid membrane; interfacial tension; surfactant; oil/water interface
