Micro Drop Actuation Using Multiplexer Structures

Digital microfluidic manipulation is analyzed for applications extending down to micron-scales. A model is introduced to study the relationship between fluid actuation forces and the resulting resistive viscous and capillary forces that dominate the fluid flow on small dimensions. The results are presented through the analysis of a dynamical model of a novel Digital Microfluidic Multiplexer structure. In essence, the multiplexer is an interdigitated structure that is used to apply electrical signals to individual drops confined between two horizontal plates, about 10–50 microns apart. The multiplexer consists of x-electrodes, installed in the bottom plate, perpendicular to the y-electrodes, installed in the top plate. It is shown that such a configuration allows for highly parallel electrode addressability within exceedingly small (micron-scale) integrated structures.