(454c) Phoretic Convective Instability at a Fluid–Fluid Interface

Diffusiophoretic flow drives relative motion near an interface by a concentration gradient of a solute which is either attracted or repelled from an interface. Due to coupling between this flow and solute advection, we show that a diffusiophoretic convective instability can arise at a fluid–fluid interface, analogous to Rayleigh–Bénard convection. Using a linear stability analysis, we show the possibility of such an instability, which does not require the external application of a solute gradient. The instability occurs for both attractive and repulsive solute–interface interactions at physically reasonable parameter values. Nonlinear simulation of the instability evolution through time will also be discussed. This mechanism provides a novel approach to explaining observed phenomena like interfacial turbulence and spontaneous emulsification.