Modeling of capillary-driven microfluidic networks using electric circuit analogy

Abstract

Capillary-driven flow in complex microfluidic devices is increasingly encountered in life science applications, and powerful modeling tools are necessary to assist the design of these devices. In this work, we present a modeling framework for capillary-driven flow in closed complex microfluidic networks using electric circuit analogy. The model handles two immiscible fluid phases, including the capillary pressure jump across the interface(s) between the phases, in a large variety of fluidic structures. As outputs, the position and velocity of each interface in the analyzed microfluidic network are provided as a function of time. Single channels, successive channels of different dimensions, tapered channels, micropillar arrays, flow splitters, mixing of two liquids, and the presence of vents can be modeled and combined in different complex structures. Static and dynamic contact angles can be employed. Advancing and receding interfaces can both be modeled. The model was validated against both experimental and analytical results for specific microfluidic structures. Furthermore, the capabilities of the model are demonstrated using a complex microfluidic network.