(461i) Electrokinetic Control of Viscous Fingering: From Theory to Experiment

Interfacial instability for two immiscible fluids are usually undesirable but difficult to control. Viscous fingering happens when a more viscous fluid is displaced by a less viscous fluid. This phenomena leads to the non-uniform displacement and trapping of the more viscous fluid. Previously, we have demonstrated in theory and simulation when the interface between two immiscible electrolytes is set into motion by both pressure driven flow and electro-osmotic flow, the interface stability can be tuned by applying electric field. This electrokinetic coupling provides a new degree of freedom to manipulating the interfacial stability between two electrolytes. It enables us to either stabilize an unstable displacement (water displacing oil), or unstablize a stable displacement (oil displacing water) by forcing current into the system. In this talk, we will present the first experiment results on electrokinetic control of viscous fingering.