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Updated: Nov 12, 2025
08:01
The Diffusion of Passive Tracers in Laminar Shear Flow
Published on: May 1, 2018
8.9K
Diffusion of colloidal particles in model porous media
Luhui Ning1,2, Peng Liu1,2, Fangfu Ye1,2,3,4
1Beijing National Laboratory for Condensed Matter Physics and Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Physical Review. E
|March 19, 2021
Summary
We discovered a universal scaling law linking tracer diffusion in porous media to structural entropy. This finding quantifies how porous media structure dictates tracer movement, extending previous scaling laws.
Area of Science:
- Colloid science
- Soft matter physics
- Statistical mechanics
Background:
- Understanding particle diffusion in complex media is crucial for various scientific fields.
- Previous studies identified scaling laws for diffusion in fluctuating media.
Purpose of the Study:
- To investigate the long-time diffusion of colloidal tracers in model porous media.
- To establish a quantitative relationship between tracer diffusion and porous media structure.
- To extend existing diffusion scaling laws to static porous systems.
Main Methods:
- Video microscopy was employed to track tracer movement.
- Computational simulations were used to model porous media structures.
- Analysis focused on the relationship between diffusion coefficients and system structures.
Main Results:
- Tracer diffusion coefficients are quantitatively determined by the structure of the porous media.
- A universal scaling relation was found between dimensionless diffusion coefficient and structural entropy.
- This relation extends previously discovered scaling laws for colloidal particle diffusion.
Conclusions:
- The structure of porous media fundamentally governs tracer diffusion dynamics.
- Structural entropy serves as a key parameter for predicting diffusion behavior.
- The discovered universal scaling law provides a novel framework for understanding transport in disordered materials.
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