Effects of viscosity on phase separation of liquid mixtures with a critical point of miscibility

Abstract

After quenching a high-viscosity partially miscible critical liquid mixture to a temperature far below the critical point, we observed the formation of rapidly coalescing droplets, whose size grew linearly with time, indicating that phase separation process is driven byconvection. As predicted by the diffuse interface model, this experimental work showed that the viscosity did not have any effect on the growth rate and the speed of the nucleatingdroplets. Eventually, when the droplets size reached its critical length, they started tosediment and separated by gravity. At this point, the viscosity influenced the settling speedand the total separation time. Key words: Phase separation, spinodal decomposition, viscosity, convection.