Study of a new multi channel foam and emulsion generator

Abstract

ABSTRACTThis work describes the design and operation of two microfluidic emulsion and foam generators. The difference between the two devices consists in the geometry of the output channel - in one case, we used a straight microchannel, whereas in the second case we implemented a fractal channel output geometry. While both devices can produce highly monodisperse foams and emulsions at high throughput (coefficient of variation CV≈1.5% and production frequency of up to 2.5kHz per channel with a total of 256 micro channels capable, in theory, of operating in parallel), the actual CV at the exit of the device was significantly higher due to interactions between adjacent droplets or bubbles. Using a combination of high-viscosity continuous phase liquid and low-solubility gas phase resulted in improved monodispersity. In these conditions, the fractal output channel geometry resulted in the lowest overall CV (≈3%) at the exit of the device for both foam and emulsion production, due to an inhibition of aging and coalescence phenomena as compared to the straight channel.