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Induced-charge electroosmotic trapping of particles
Yukun Ren1, Weiyu Liu, Yankai Jia
1School of Mechatronics Engineering, Harbin Institute of Technology, West Da-zhi Street 92, Harbin, Heilongjiang, PR China 150001. rykhit@hit.edu.cn.
Lab on a Chip
|April 2, 2015
Summary
Particle trapping on metal strips is controlled using induced-charge electroosmotic (ICEO) flow. Stable trapping occurs above a critical frequency, allowing flexible manipulation of microparticles in microfluidic systems.
Area of Science:
- Physics
- Fluid Dynamics
- Microfluidics
Background:
- Induced-charge electroosmotic (ICEO) flow is a key phenomenon in microfluidics.
- Controlling particle manipulation in microfluidic devices is crucial for various applications.
Purpose of the Study:
- To demonstrate position-controllable trapping of particles using ICEO flow on a bipolar metal strip.
- To investigate the influence of ICEO slip profiles and AC field parameters on particle trapping.
Main Methods:
- Utilizing a bipolar metal strip to generate ICEO flow.
- Analyzing nonlinear and linear ICEO slip profiles under different frequency regimes (DC vs. AC).
- Extending AC-flow field-effect transistor principles to control ICEO.
Main Results:
- Stable particle trapping was achieved above the double-layer relaxation frequency due to a nonlinear ICEO slip profile.
- No trapping occurred in the DC limit because of upward fluidic drag from a linear ICEO slip profile.
- Fixed-potential ICEO exceeding RC charging frequency enabled flexible adjustment of particle trapping positions by controlling vortex flow symmetry.
Conclusions:
- Nonlinear ICEO slip profiles are essential for stable particle trapping.
- AC field control of ICEO flow offers flexible manipulation of microscopic objects.
- This research provides new avenues for microparticle manipulation in microfluidic systems.
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