Experimental investigation of jamming in porous media by microgel suspensions.

Suspension flows in porous media are used in many industrial applications. Clogging of the porous media and suspension's filtration are key issues encountered in these applications. These phenomena are complex processes and in order to get a better understanding of them, we perform experiments to investigate the jamming dynamics of microgel suspensions in microfluidic devices to mimic model porous media. We study how parameters like surface wettability, particle concentration, particle size and flow rates affect the filter cake formation. We exploit phase contrast microscopy for direct observation of the clogging of porous media by microgel particles. In situ Raman spectroscopy is also used to determine the local concentration of the jammed microgel in the filter cake inside the microfluidic geometry. Additionally, we investigate the rheological behavior in microchannels to understand the effect of confinement on the rheology. Our experiments reveal that the microgel particles have more affinity for a hydrophilic surface which eventually assists in jamming. We report that the rate of formation of the filter cake for cross flow filtration geometry is dependent on pore size/ particle size ratio.