Abstract
We present a comprehensive study of the step-emulsification process for high-throughput production of colloidal monodisperse droplets. The 'microfluidic step emulsifier' combines a shallow microchannel operating with two co-flowing immiscible fluids and an abrupt (step-like) opening to a deep and wide reservoir. Based on Hele-Shaw hydrodynamics, we determine the quasi-static shape of the fluid interface prior to transition to oscillatory step-emulsification at low capillary numbers. The theoretically derived transition threshold yields an excellent agreement with experimental data. A closed-form expression for the size of the droplets generated in the step-emulsification regime and derived using geometric arguments also shows a very good agreement with the experiment.
| Original language | English |
|---|---|
| Pages (from-to) | 1023-1031 |
| Number of pages | 9 |
| Journal | Lab on a Chip |
| Volume | 15 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 2015 |
| Externally published | Yes |
Keywords
- Hele-shaw cell
- Membrane emulsification
- Interfacial-tension
- Droplet formation
- Viscous-fluid
- Generation
- Bubbles
- Breakup
- Driven
- Array