Novel parallel integration of microfluidic device network for emulsion formation

This work describes a design strategy to scale up microfluidics for producing monodispersed emulsions. Scale-up to 180 microfluidic devices with tight distribution of droplet size has been achieved (coefficient of variation CV ≃ 5%) by designing a system that is capable of operating easily without active control on single devices within the microfluidic platform. This has been achieved by using existing knowledge gained in the formation of monodispersed emulsions using a single device. We have identified three important factors affecting the scale-up of microfluidic systems that can benefit industrial scale-up processing. First, we used a network model simulation (Matlab) to evaluate two different branching layouts used to distribute liquids from a single manifold into the parallelized device network. We checked how fabrication tolerances could affect droplet formation, and as a result of this step, the ladder-type layout was preferred to the tree-type arrangement. The second important contribution of this work is the introduction of separate drainage manifolds for the two phases connecting all the input streams which have improved the performance and the operability of the system. Finally, we introduced a large opening after a short channel (150 μm) downstream of the junction where the droplet is formed. This opening acts like a reservoir to damp any pressure variation which could travel back to the inlet point and disturb the flow of neighboring devices. © 2009 American Chemical Society