Synchronous Droplet Microfluidics: One "Clock" to rule them all

Controlling fluid droplets efficiently in the microscale is of great interest both from a basic science and a technology perspective. We have designed and developed a general-purpose, highly scalable microfluidic control strategy through a single global clock signal that enables synchronous control of arbitrary number of droplets in a planar geometry. A rotating precessive magnetic field provides a global clock signal, enabling simultaneous control of droplet position, velocity and trajectories. Here, in this fluid dynamics video, we explain the main physics of this new microfluidic concept. Video data from droplets moving in sync in different fluidic circuits are included. The experimental setup is described and video data is analyzed to provide a detailed view of the time-dynamics of propagating droplets. Finally, we explore the operational limits of this concept, scaling and phase diagram with physical regime diagram.