A droplet-based microfluidic system capable of droplet formation and manipulation

Formation of emulsion droplets is crucial for a variety of industrial and scientific applications. This study presents a new droplet-based microfluidic system capable of generating tunable and uniform-sized droplets and subsequently deflecting these droplets at various inclination angles using a combination of flow-focusing and moving-wall structures. A pneumatic air chamber was used to activate the moving-wall structures, located nearby the outlet of the flow-focusing microchannels, such that the sheath flows can be locally accelerated. With this approach, the size of the droplets can be fine-tuned and sorted without adjusting the syringe pumps. Experimental data showed that droplets with diameters ranging from 31.4 to 146.2 mu m with a variation of less than 5.39% can be generated. Besides, droplets can be sorted upwards or backwards with an inclination angle ranging from 0A degrees to 53.5A degrees. The development of this emulsion system may be promising for the formation and collection of emulsion products for applications in the pharmaceutical, cosmetics and food industries.