Solutal Marangoni effect

Abstract The motion of a nitroethane lens located at the surface of an aqueous solution of dodecyltrimethylammonium bromide is analyzed. This motion is generated by a solutal Marangoni effect, or soluto—capillary instability, induced by the transfer of the surfactant from one phase to the second one, both solvents being mutually saturated; its quasi-periodic character is demonstrated by a statistical and spectral analysis, and its characteristics, amplitude, and frequency are discussed as a function of the physicochemical conditions. The enhancement of the interfacial transfer by the Marangoni effect is evaluated. It is shown that none of the available models of linear stability analysis can account for the present results.