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Droplet-based electro-coalescence for probing threshold disjoining pressure.
Zhou Liu1, San To Chan, Hammad Ali Faizi
1Department of Mechanical Engineering, Haking Wong Building, The University of Hong Kong, Hong Kong. ashum@hku.hk.
Lab on a Chip
|March 17, 2015
Summary
Controlled electric fields induce emulsion droplet coalescence above a critical voltage. This study presents a new method to measure the threshold disjoining pressure, enhancing emulsion stability prediction.
Area of Science:
- Colloid and Surface Science
- Materials Science
- Physical Chemistry
Background:
- Emulsion stability is crucial for formulations.
- Droplet coalescence is a key destabilization mechanism.
- Surfactant properties significantly influence coalescence.
Purpose of the Study:
- To investigate electric field-induced emulsion droplet coalescence.
- To develop a quantitative method for predicting emulsion stability.
- To determine the threshold disjoining pressure using an electric field approach.
Main Methods:
- Applying a controlled electric field to induce droplet coalescence.
- Analyzing the drainage of the thin oil film between droplets.
- Measuring critical voltages and correlating them with surfactant properties and temperature.
Main Results:
- A critical voltage was identified for initiating coalescence.
- The critical voltage is dependent on surfactant type, concentration, and temperature.
- The electric field approach successfully determined threshold disjoining pressure.
Conclusions:
- Electric field-induced coalescence provides a method to probe emulsion stability.
- The developed approach offers a simple, reliable, and robust way to predict emulsion stability and surfactant efficacy.
- This facilitates the accelerated design of emulsion-based formulations.
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