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Updated: Apr 12, 2026
10:56
Confocal Imaging of Confined Quiescent and Flowing Colloid-polymer Mixtures
Published on: May 20, 2014
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Two spheres translating in tandem through a colloidal suspension.
1Department of Chemical and Biomolecular Engineering, Center for Molecular and Engineering Thermodynamics, University of Delaware, Newark, Delaware 19716, USA.
Summary
Two colloidal particles in a flowing suspension experience identical drag forces. Their interaction influences the surrounding fluid microstructure, reducing drag compared to isolated particles.
Area of Science:
- Colloidal science
- Fluid dynamics
- Soft matter physics
Background:
- Understanding particle interactions in dense suspensions is crucial for material science.
- Hydrodynamic interactions govern the collective behavior of particles in fluids.
Purpose of the Study:
- To investigate the influence of probe particle separation and velocity on suspension microstructure.
- To quantify the drag forces on probe particles within a flowing suspension.
Main Methods:
- Utilizing laser tweezers to position two colloidal probe particles.
- Employing confocal microscopy to image local suspension deformation.
- Measuring drag forces on probe particles as a function of separation and velocity.
Main Results:
- Observed changes in bath microstructure influenced by probe velocity and separation.
- Identified a depleted region between probes at high velocities.
- Found that both probes experience equal drag, increasing with separation.
Conclusions:
- Bath-probe and probe-probe hydrodynamic interactions significantly affect microstructure and drag.
- Direct bath-probe collisions reduce drag compared to an isolated probe scenario.
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