Forced drainage and imbibition in microfluidic porous media

We present an experimental study on the dynamics of two-phase flow in microfabricated porous media. In particular we focus on pressure-driven imbibition and drainage in two-dimensional networks of microchannels. We vary the geometrical features of the network, viscosity of the non-wetting fluid and surface chemistry of the microchannels. The rate of displacement and entrapment of the liquid are studied. A simple model that accounts for capillary and viscous effects is compared with the experimental results.