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Actuation of Flexible Membranes via Capillary Force: Single-Active-Surface Experiments
Christina Barth1, Carl Knospe2
1Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA 22904, USA. cab5sf@virginia.edu.
Micromachines
|February 5, 2019
Summary
This study introduces a novel microactuator using electrowetting on a single active surface to control capillary pressure, achieving significant membrane deflection at moderate voltages for lab-on-a-chip applications.
Area of Science:
- Microfluidics
- MEMS (Micro-Electro-Mechanical Systems)
- Actuation Technologies
Background:
- Conventional microscale actuation methods struggle with large motion at moderate voltages.
- Electrowetting-based actuators utilize capillary pressure changes for actuation.
- Existing electrowetting actuators often require two active surfaces.
Purpose of the Study:
- To investigate the efficacy of a single active surface electrowetting actuator.
- To demonstrate significant membrane deflection using controlled capillary pressure.
- To analyze design parameters influencing actuator performance.
Main Methods:
- Experimental testing of five prototype devices with a single active surface.
- Application of electrowetting to induce capillary pressure changes in a liquid bridge.
- Measurement of flexible membrane deflection under varying design conditions.
- Comparison of experimental results with theoretical predictions.
Main Results:
- Achieved large membrane deflections up to 15 μm.
- Utilized moderate voltages (≤25 V).
- Demonstrated the influence of membrane diameter and thickness on deflection.
- Theoretical predictions showed good agreement with experimental data.
Conclusions:
- Single active surface electrowetting actuators provide a simplified approach for microscale actuation.
- This method achieves adequate deflections for lab-on-a-chip microsystems.
- Further investigation into discrepancies between theory and experiment is warranted.
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