Upscaling microfluidic emulsification: the importance of sub-structure design in EDGE devices

Summary

When used for emulsion production, microfluidics are known for their low energy usage and droplet monodispersity. However, current throughputs need to be improved to realize larger scale microfluidic emulsion production. Here, we present the upscaled device called Multi EDGE, which we use to produce 10-µm hexadecane droplets in 0.5 wt% SDS solution at 0.3 m³/m²h in a proof of concept study. The design of the dispersed phase supply channels is crucial, since a higher flow resistance causes a higher blow-up pressure and faster pore refilling. In turn, this results in high droplet formation frequencies of >1800 droplet s⁻¹ per droplet formation unit, compared to maximally 60 droplet s⁻¹ per droplet formation unit for devices with low-resistance substructure, which are limited by the refilling process. The fluxes and small droplets of Multi EDGE, show that these devices have potential for upscaling, especially when the substructure is designed properly.