Related Experiment Video
Updated: Jul 2, 2026
08:58
Double Emulsion Generation Using a Polydimethylsiloxane (PDMS) Co-axial Flow Focus Device
Published on: December 25, 2015
Controlled encapsulation and droplet size prediction in two-step microfluidic double emulsions
Chen Tang1, Loïc Chagot2, Panagiota Angeli1
1ThAMeS Multiphase, Department of Chemical Engineering, University College London, UK. p.angeli@ucl.ac.uk.
Lab on a Chip
|July 1, 2026
Summary
Researchers developed a model to predict the size of water-in-oil-in-water double emulsion droplets created using microfluidics. This model aids in controlling droplet generation for encapsulation and controlled release applications.
Area of Science:
- Microfluidics
- Colloid and Interface Science
- Materials Science
Background:
- Double emulsions (w1/o/w2) are crucial for encapsulation and controlled release in microfluidic systems.
- Controlling the size and formation of these droplets is essential for their application efficacy.
Purpose of the Study:
- To investigate the formation regimes of double emulsion droplets produced via a two-step flow-focusing process.
- To develop a predictive model for double droplet size in microfluidic applications.
- To understand the influence of surfactant concentration and interfacial tension on droplet formation.
Main Methods:
- Utilized a two-step flow-focusing microfluidic device.
- Employed a low-viscosity silicone oil and an aqueous phase of water and glycerol.
- Varied Sodium dodecyl sulfate (SDS) concentrations (0.2, 0.5, 1, 2 times CMC) to alter interfacial tension.
- Identified three distinct droplet formation regimes: drop-in-drop, drop-in-plug, and drop-in-thread.
Main Results:
- Identified three distinct formation regimes (drop-in-drop, drop-in-plug, drop-in-thread) based on flow rate ratios and interfacial tension.
- Developed a semi-empirical model that accurately predicts double droplet size in the drop-in-drop regime.
- Achieved mean absolute percentage errors (MAPE) of 8.16% for core droplets and 9.54% for double droplets with the model under equilibrium interfacial tension conditions.
- Incorporating dynamic interfacial tension improved prediction accuracy (MAPE of 8.17%) for lower surfactant concentrations.
Conclusions:
- The developed semi-empirical model provides a quantitative framework for predicting double emulsion droplet size in microfluidics.
- The findings offer practical operating guidance for the controlled generation of encapsulated droplets.
- Understanding interfacial tension effects is key to optimizing microfluidic double emulsion production.
