Control of Ferrofluid Droplets in Microchannels by Uniform Magnetic Fields

Magnetic droplets are versatile tools for a range of lab-on-a-chip (LoC) applications. The combination of a uniform magnetic field and magnetic droplet offers wireless and programmable manipulation. We performed LoC experiments and numerical studies on ferrofluid droplets under the influence of a uniform magnetic field. The dynamic behavior of flowing ferrofluid droplets was examined. The droplet size, shape, interdroplet spacing and velocity could be controlled by tuning the magnetic susceptibility of the ferrofluid, the viscosity of the carrier medium, and the flow rates. Our droplet-based micromagnetofluidic numerical model is in good agreement with our experiments. These studies are useful for magnetic droplet control and mixing in a LoC using a uniform magnetic field.