Capillary imbibition in lubricant-coated channels

Abstract

Capillary imbibition underpins many processes of fundamental and applied relevance in fluid mechanics. A limitation to the flow is the coupling to the confining solid, which induces friction forces. Here we study the effect of coating the solid with a liquid lubricant layer. Using a theoretical framework, we show that for sufficiently small lubricant viscosity, dissipation entirely occurs in the lubricant layer, resulting in a linear growth of the advancing front. We extend our study to forced imbibition, where the same mechanism gives rise to an exponential front growth. This new ability to control multiphase flows in confinement opens new opportunities for flow control in micro and nanofluidic devices.