Abstract:

A complex solute Marangoni instability phenomena is observed by analysing the motion of a nitroethane droplet located at the surface of an aqueous solution of 2-butanol. It is shown that the motion in the first five minutes is composed of three successive phases with different dynamic properties-oscillatory, stationary and spiral.
A self-induced complex mechanism is used to explain this phenomena. It is proposed that the basic origin of this instability is the transfer of the surface-active 2-butanol, but this transfer diminishes the subsurface concentration of 2-butanol in the aqueous phase and induces the restoration of the equilibrium of mutual solubility of the two solvents-nitroethane and water, which has a complex effect on this interfacial phenomena.

Key words: Interfacial instability, Marangoni effect, Interfacial tension gradient, 2-butanol;Nitroethane