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Dispersion of self-propelled rods undergoing fluctuation-driven flips
Daisuke Takagi1, Adam B Braunschweig, Jun Zhang
1Applied Math Lab, Courant Institute, New York University, New York, New York 10012, USA.
Physical Review Letters
|February 5, 2013
Summary
Synthetic microswimmers, designed for medical and technological applications, exhibit unpredictable motion. Minor shape defects in these chemically propelled rods cause significant long-term dispersion, impacting their overall behavior.
Area of Science:
- Soft Matter Physics
- Microfluidics
- Chemical Engineering
Background:
- Synthetic microswimmers offer potential for advanced applications, but their complex motion and dispersion patterns remain challenging to predict.
- Understanding the factors influencing microswimmer trajectory is crucial for harnessing their capabilities in fields like targeted drug delivery and micro-assembly.
Purpose of the Study:
- To investigate the motion and dispersion of chemically propelled rod-shaped microswimmers on a surface.
- To elucidate the role of shape fluctuations and minor defects in dictating the macroscopic behavior of synthetic microswimmers.
Main Methods:
- Experimental observation of chemically propelled rods on a surface.
- Theoretical modeling incorporating fluctuation-driven flipping of slightly curved rods.
- Analytical prediction of ensemble behavior.
Main Results:
- Chemically propelled rods primarily move along large circular paths on a surface.
- Stochastic changes in the curvature sign of the rods' orbits were observed.
- Analytical predictions derived from accounting for minor shape defects showed strong agreement with experimental results.
Conclusions:
- Slight curvature defects in synthetic microswimmers can lead to significant, long-term effects on their macroscopic dispersion.
- Fluctuation-driven flipping is a key mechanism explaining the observed stochastic changes in motion.
- This work highlights the importance of precise microfabrication for controlling microswimmer behavior and dispersion.
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