Oil in Water Emulsions
Oil in Water emulsions (O/W) are widely used in industrial and R&D environments to manufacture droplets (e.g., for compartmentalization applications), wax beads (e.g., carnauba or cosmetic wax), and polymer beads (e.g., PLGA, Styrene, methacrylates, etc.). Of particular importance is the ability to produce high-quality, monodisperse droplets and the ability to do so reproducibly and at a viable production rate.
The combination of Pressure based flow controller units and RayDrop microfluidic devices developed and manufactured by Secoya enable smooth fluid delivery, precision flowrate control, automation, and reproducibility necessary to generate high-quality oil in water emulsions.
Materials and methods
Reagents
Droplet Phase: Decane
Continuous phase: Water + 2% (wt) Sodium dodecyl sulfate (SDS)
| Reagent | Supplier | Catalogue number | CAS Number |
| Water | Ultrapure 18.2 MΩ – cm | – | 7732-18-5 |
| Decane | Sigma Aldrich | D901 | 124-18-5 |
| Sodium dodecyl sulfate | Sigma Aldrich | 436143 | 151-21-3 |
Microfluidic Setup
The microfluidic setup was composed of:
Protocols steps
Results
| Continuous phase flowrate (μl/min) | Droplet phase flowrate (μl/min) | Droplet diameter (μm) | Production rate (Hz) |
| 100 | 5 | 63 | 637 |
| 100 | 10 | 67 | 1058 |
| 100 | 15 | 73 | 1227 |
| 50 | 5 | 71 | 445 |
| 50 | 10 | 75 | 754 |
| 50 | 15 | 82 | 866 |
| 5 | 5 | 75 | 377 |
| 25 | 10 | 77 | 697 |
| 25 | 15 | 81 | 898 |
| 15 | 15 | 83 | 835 |
Conclusion
Fluigent pressure-based flow controller units and Raydrop microfluidic device were successfully used to generate high-quality, monodisperse droplets of decane in water. The droplet size was controlled in the range of 63 – 83 μm by adjusting the continuous and dispersed phase flowrates. Peak stable droplet production rate was recorded for 73 μm droplets at 1227 Hz. The production techniques developed here can be extended to the generation of wax, p, or polymer beads by adding suitable post-processing steps.