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Driven dynamics in dense suspensions of microrollers
Brennan Sprinkle1, Ernest B van der Wee, Yixiang Luo
1Courant Institute of Mathematical Sciences, New York University, New York, NY 10012, USA.
Soft Matter
|August 11, 2020
Summary
Dense suspensions of magnetic microrollers separate into slow and fast layers, a phenomenon accurately predicted by new computational methods that include particle interactions. This confirms previous theoretical predictions and experimental observations.
Area of Science:
- Colloidal science
- Soft matter physics
- Computational fluid dynamics
Background:
- Dense suspensions of active colloidal particles exhibit complex emergent behaviors.
- Previous studies predicted layer separation in sedimented microrollers at high densities.
Purpose of the Study:
- To computationally and experimentally investigate the driven dynamics of dense, sedimented microroller suspensions.
- To develop and validate a lubrication-corrected Brownian dynamics method for these systems.
Main Methods:
- Developed a lubrication-corrected Brownian dynamics method incorporating lubrication friction.
- Used fluorescent labeling and particle tracking for experimental measurements.
- Compared computational predictions with experimental data.
Main Results:
- Verified the predicted separation into slow (bottom) and fast (top) layers.
- Achieved quantitative agreement between simulated and experimental particle velocity distributions.
- Accurately predicted particle layer-switching rates.
Conclusions:
- The developed computational method accurately models dense microroller suspensions.
- Pairwise lubrication is crucial for motility-induced phase separation in these systems.
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