Effects of unsteadiness of the rates of flow on the dynamics of formation of droplets in microfluidic systems

摘要

Oscillations of the input rates of flow have a significant impact on the dynamics of formation of droplets in microfluidic systems and on the quality of generated emulsions. One of the fundamentals of interest in microfluidic systems is the one-to-one, linear and smooth correspondence between the input parameters and the flow within the chip. This feature is rooted in the Stokes equations of flow at low Reynolds numbers and enables engineering of spatial and temporal distribution of solutes in microchannels and a variety of analytical applications. In spite of the complications associated with interfacial forces, multiphase microflows surrender to similarly extensive control. The ability to form monodisperse droplets in micro-channels inspired the use of microfluidic droplet generators both in preparatory and analytical applications. It is possible to form multiple droplets, anisotropic particles of a variety of materials and capsules with potential for use in food, cosmetics and pharmaceutical industries. Microdroplets can serve as reaction beakers yielding superior control over conditions of reactions, ultra small reaction volumes, fast mixing, lack of dispersion of time of residence and phenomenal statistics. It is possible to encapsulate single cells within droplets and to conduct ultra-fast directed evolution. Precise control over the volumes of droplets is critical in sustaining superior characteristics of e.g. drug-delivery vehicles or reliable statistics in high throughput studies.