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Updated: May 26, 2026
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The Assembly and Application of 'Shear Rings': A Novel Endothelial Model for Orbital, Unidirectional and Periodic Fluid Flow and Shear Stress
Published on: October 31, 2016
Assembly of vorticity-aligned hard-sphere colloidal strings in a simple shear flow
Xiang Cheng1, Xinliang Xu, Stuart A Rice
1Laboratory of Atomic and Solid State Physics and Department of Physics, Cornell University, Ithaca, NY 14853, USA. xc92@cornell.edu
Summary
Shear flow surprisingly forms log-rolling colloidal strings perpendicular to flow, not along it. This discovery reveals new methods for assembling large-scale particle structures using hydrodynamic interactions.
Area of Science:
- Soft Matter Physics
- Colloidal Science
Background:
- Colloidal suspensions form diverse equilibrium structures.
- Out-of-equilibrium assembly mechanisms, especially under shear, are poorly understood.
- Previous studies predicted flow-aligned strings in sheared hard-sphere colloids.
Purpose of the Study:
- To investigate shear-induced colloidal suspension structures.
- To elucidate the mechanisms behind out-of-equilibrium colloidal assembly.
- To explore novel methods for particle structure assembly.
Main Methods:
- Confocal microscopy to visualize particle arrangements.
- Stokesian dynamics simulations to model particle interactions.
- Analysis of hydrodynamic and interparticle forces.
Main Results:
- Observed log-rolling strings of colloidal particles oriented normal to the shear plane.
- Contradicted predictions of flow-aligned string formation.
- Demonstrated that emergent structures result from a balance of forces.
Conclusions:
- Shear flow can drive colloidal self-assembly into unexpected structures.
- Log-rolling strings represent a novel out-of-equilibrium assembly.
- This work provides a new approach for large-scale particle structure fabrication.
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