Related Experiment Video
Updated: Sep 30, 2025
10:03
The Preparation of Electrohydrodynamic Bridges from Polar Dielectric Liquids
Published on: September 30, 2014
26.6K
Fluid pumping by liquid metal droplet utilizing ac electric field
Chun-Lei Song1, Ye Tao1,2, Wei-Yu Liu3
1State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin 150001, China.
Physical Review. E
|March 16, 2022
Summary
Liquid metal droplets (LMDs) in an AC electric field exhibit unique fluid pumping. Shifting the droplet
Area of Science:
- Fluid dynamics
- Electrokinetics
- Materials science
Background:
- Traditional fluid pumping with liquid metal droplets (LMDs) relies on DC electric fields, limiting directional control.
- Existing models for LMD/electrolyte interfaces often fail to accurately predict flow direction with non-negligible oxide skin thickness.
Purpose of the Study:
- To investigate and explain a novel fluid pumping phenomenon using liquid metal droplets (LMDs) under a pure AC electric field.
- To develop a new physical model accounting for nonlinear electrocapillary stress and oxide layer properties in LMDs.
- To demonstrate controllable, directional fluid pumping by manipulating LMD position within an AC electric field.
Main Methods:
- Experimental setup utilizing a pure AC electric field to induce fluid motion via liquid metal droplets (LMDs).
- Development of a nonlinear physical model treating the oxide layer as a distributed capacitance connected to the electric double layer.
- Microparticle imaging velocimetry (μPIV) for flow visualization and comparison with simulation results from the proposed nonlinear model.
Main Results:
- Demonstrated unique fluid pumping by LMDs in an AC electric field, with flow direction switchable by altering LMD position.
- Identified Marangoni flow, driven by nonlinear electrocapillary stress from a localized, asymmetric AC field, as the pumping mechanism.
- The developed nonlinear model accurately predicts flow profiles, outperforming traditional linear models for LMDs with significant oxide layers.
Conclusions:
- A novel method for stable, adjustable, directional fluid pumping of low-conductivity solutions using LMDs in a zero-mean AC electric field is presented.
- The study elucidates the underlying physics of AC-field-induced Marangoni flow in LMDs, considering oxide layer effects.
- This work offers a new paradigm for microfluidic manipulation and pumping without the need for DC field polarity reversal.
