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Coalescence of electrically charged liquid marbles
Zhou Liu1, Xiangyu Fu2, Bernard P Binks3
1Microfluidics & Soft Matter Group, Department of Mechanical Engineering, University of Hong Kong, Pokfulam Road, Hong Kong, China. ashum@hku.hk and HKU-Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong 518000, China.
Soft Matter
|May 24, 2016
Summary
We found that applying a DC electric field can induce the electro-coalescence of liquid water marbles. The required voltage depends on particle stabilizers and surface tension, enabling controlled merging for potential applications.
Area of Science:
- Physics
- Materials Science
- Fluid Dynamics
Background:
- Liquid marbles are micro-reactors offering unique surface properties.
- Controlling liquid marble interactions is crucial for advanced applications.
Purpose of the Study:
- To investigate the electro-coalescence of liquid water marbles under a DC electric field.
- To determine the factors influencing the threshold voltage for electro-coalescence.
- To explore the potential of electro-coalescence in multi-reagent systems.
Main Methods:
- Applying a DC electric field to contacting liquid water marbles.
- Varying stabilizing particle types and aqueous phase surface tension.
- Analyzing electric stress, capillary pressure, and scaling relations.
- Developing and validating a model for multi-marble electro-coalescence.
Main Results:
- Two contacting liquid marbles coalesce above a critical DC voltage.
- Threshold voltage is sensitive to stabilizing particles and surface tension.
- Coalescence is driven by electric stress forming a connecting liquid bridge.
- Multiple marbles in a chain exhibit linear voltage dependency for coalescence.
- A predictive model for threshold voltage and marble number shows good agreement.
Conclusions:
- Electro-coalescence provides a method to merge liquid marbles controllably.
- The phenomenon is governed by a balance between electric stress and capillary pressure.
- This technique offers potential for microfluidic applications and multi-reagent reactions.
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