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Size-Dependent Localization in Polydisperse Colloidal Glasses
D Heckendorf1, K J Mutch1, S U Egelhaaf1
1Condensed Matter Physics Laboratory, Heinrich Heine University, Universitätsstrasse 1, 40225 Düsseldorf, Germany.
Physical Review Letters
|January 18, 2018
Summary
Concentrated suspensions of hard spheres show differing particle dynamics with size. Large particles move slower and localize more, linking local crowding to heterogeneous dynamics, but collective effects are key to arrest.
Area of Science:
- Soft Matter Physics
- Colloidal Science
- Materials Science
Background:
- Understanding particle dynamics in concentrated suspensions is crucial for materials science.
- Polydispersity in particle size can significantly influence suspension behavior.
- Confocal microscopy enables detailed observation of individual particle motion.
Purpose of the Study:
- To investigate the dynamics and sizes of individual particles in concentrated polydisperse hard sphere suspensions.
- To explore the relationship between particle size, local crowding, and dynamics.
- To understand the factors contributing to dynamical arrest in these systems.
Main Methods:
- Utilized confocal microscopy to track individual particles in concentrated suspensions.
- Analyzed particle dynamics and determined particle sizes.
- Calculated local volume fraction (ϕ_loc) and localization length.
Main Results:
- Observed differing dynamics between small and large particles with increasing concentration.
- Large particles exhibited slower dynamics and stronger localization.
- Localization length decreased significantly beyond ϕ_loc ≈ 0.67, suggesting a link between local crowding and dynamical heterogeneities.
Conclusions:
- Local crowding is linked to dynamical heterogeneities in concentrated suspensions.
- Dynamical arrest of subpopulations is not solely dependent on high local volume fraction.
- Collective effects play a significant role in the dynamical arrest of particles.
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