Coriolis-Induced Flow Control for Micro- and Nanofluidic Lab-on-a-Disk Technologies

This paper investigates how the Coriolis force can be user to control and pattern flow on a centrifugal microfluidic platform. This platform is composed of a drive unit resembling a standard CD player to spin a microstructured CD. The centrifugally driven flow on this CD is guided by microfluidic channel structures from inlet ports near the center towards the waste reservoirs on the outer perimeter. To demonstrate a Coriolis-controlled actuation, we first present a microfluidic flow switch which changes the ratio of the flow rates through two symmetric outlet channels according to the frequency and sense of rotation. Furthermore, we demonstrate that by means of the hydrodynamic interactions of the Coriolis-force and the channel geometry, a self-patterning of flow can be achieved. This effect is implemented for a novel type of micromixer based on the multilamination of flow. The remarkable aspect of this mere hydrodynamic effect is that the guide structures are represented by a simple, 2dimensional network of low-aspect-ratio rectangular channels, featuring less complexity than the final flow pattern. This method of self-patterning could thus offer a novel top-down approach towards nanofabrication enabled by microfluidics.