Arresting of interfacial phase separation with an imposed flow

Using fluid displacement in a Hele-Shaw cell, we experimentally demonstrate the arresting effect of an imposed flow on a phase separation occurring in a growing liquidliquid interfacial region, unlike in an initially homogeneous single-phase mixture quenched within the miscibility gap. Increasing the imposed flow rate reduces the exponent alpha in the form AA proportional to t alpha, where AA is the increase in the area occupied by the displacing fluid owing to phase separation. We show that alpha can be expressed as a function of the ratio of the phase separation rate to the flow rate on a single curve, indicating that the competition between the imposed flow and phase separation rates determines the degree of the interfacial phase separation. The arresting effect and the mechanism are verified by a numerical simulation.