Capillary passive valve in microfluidic systems

Abstract

This work reports the theoretical and experimental investigations of capillary bust valves to regulate liquid flow in microchannels. The theoretical analysis uses the Young-Laplace equation and geometrical considerations to predict the pressure at the edge of the valve opening. Numerical simulations are employed to predict the meniscus shape evolution while the interface is pinned at the valve edge. Microchannel and valves are fabricated using the soft lithography. A wafer-rotating system, which can adjust a driving pressure by rotational speed, induces a liquid flow. Experimentally measured valve-bursting pressure agrees with theoretical predictions.