Rheology of ordered foams—on the way to Discrete Microfluidics

Microfluidics is a rapidly developing field of innovation, which provides the chemical, medical and (bio)pharmaceutical industries with a much more efficient substitute for the use of well plates, syringes, etc., to perform multiple manipulations and analysis of small samples. While conventional, continuous microfluidics and the manipulation of individual nano-droplets in “Digital Microfluidics” are highly advanced, a major new dimension is added by our work on the flow of ordered foam and emulsion structures in specifically designed channel geometries. We show experimentally and computationally, utilizing both the quasi-static and Viscous Froth models, how the interplay between channel geometry and ordered foam/emulsion structures can be used to process tiny amounts of gases or liquids in a highly reliable and efficient way. We have termed this method “Discrete Microfluidics” and will introduce its various aspects in this paper.