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Bubble removal in microfluidic channels surrounded by gas-permeable media: experiments and a predictive model
Ludovic Keiser1,2, Loukas Stamoulis1, Baptiste Georjon1
1Univ. Grenoble Alpes, CNRS, LIPhy, 38000 Grenoble, France. benjamin.dollet@univ-grenoble-alpes.fr.
Lab on a Chip
|August 19, 2025
Summary
Gas permeation through microchannel walls removes trapped air, offering a bubble-free solution for microfluidic devices. This study details bubble elimination dynamics and influencing factors.
Area of Science:
- Microfluidics
- Fluid Dynamics
- Materials Science
Background:
- Controlling bubble removal is vital in microfluidics for eliminating unwanted air pockets.
- Receding bubbles can induce liquid flows in pumpless microfluidic applications.
Purpose of the Study:
- To understand the physical dynamics of air removal in microchannels.
- To investigate the role of gas permeation in bubble elimination.
Main Methods:
- Studied wetting liquid invasion in dead-end microchannels made of polydimethylsiloxane (PDMS).
- Systematically varied channel geometry (width, height) and PDMS thickness.
- Developed an analytical model coupling capillarity and gas diffusion.
Main Results:
- Observed exponential decay in trapped air length due to gas permeation, contrasting with the Lucas-Washburn law.
- Identified geometric and material factors influencing the refilling timescale.
- Validated the analytical model quantitatively.
Conclusions:
- Gas permeation provides an effective, passive route for bubble elimination in microchannels.
- The developed model accurately predicts bubble removal dynamics.
- Offers practical guidelines for microfluidic engineers to manage trapped air without active pumping.
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