Dynamics of electroosmotic switching of reacting microfluidic flows

This work presents a detailed theoretical and experimental investigation of the dynamics of electroosmotic switching of flows in a microchannel 'Y' junction. The work is considered directly relevant to the design of slug flow reactors and to flow stream switching in high throughput microfluidic testing systems. It considers reagents and products with both uniform and non-uniform properties and shows that the normally accepted, simple view of clean switching is rarely achieved in practice. Instead there is contamination of each reagent supply channel with the other reagent. The dependence of this contamination on the properties of the fluids has been addressed in a simple model that serves to illustrate well the observed behaviour of the interfaces formed by switching.