MODELING OF THE CAPILLARY-DRIVEN FLOW BETWEEN ROUGH SURFACES
Many natural and engineered systems involve a thin liquid film between two solid surfaces. Familiar examples in nature include: plants and trees, which transport fluid from roots to leaves in opposition of gravity through xylem conduits; and soils whose strength characteristics depend on the way water interacts between solid particles. Among engineered systems, there are several small scale devices for which liquids are present in confined regions during fabrication or during operation. In many cases, the presence of the liquid film causes excessive adhesive forces and device failure. On the positive side, in the operation of nanofluidic devices, capillary forces operating in submicron channels are used to pump liquids from one location to another. In this work, a model for the capillary flow between two nominally flat rough surfaces is presented. The current model represents an extension to the previous published models of liquid-mediated adhesion.