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Published on: May 20, 2014
Dynamics of permeable particles in concentrated suspensions
Gustavo C Abade1, Bogdan Cichocki, Maria L Ekiel-Jezewska
1Institute of Theoretical Physics, University of Warsaw, Hoza 69, 00-681 Warsaw, Poland.
Summary
We studied how porous colloidal particles diffuse in fluids. Particle permeability significantly affects diffusion and sedimentation, but the hydrodynamic function shows a universal behavior across different permeabilities.
Area of Science:
- Colloid science
- Fluid dynamics
- Materials science
Background:
- Colloidal suspensions are ubiquitous in nature and industry.
- Understanding particle diffusion is crucial for predicting suspension behavior.
- Porous particles introduce complex hydrodynamic interactions not present in hard spheres.
Purpose of the Study:
- To investigate the short-time diffusion properties of permeable colloidal spheres.
- To analyze the impact of particle permeability on hydrodynamic functions, sedimentation, and self-diffusion.
- To explore the concentration dependence of these properties across the full fluid-phase range.
Main Methods:
- Modeling particles as uniform permeability spheres with excluded volume interactions.
- Utilizing a precise multipole method implemented in the HYDROMULTIPOLE program.
- Accounting for many-body hydrodynamic interactions in calculations.
Main Results:
- Self-diffusion coefficients and sedimentation coefficients are highly dependent on particle permeability.
- The wave-number dependence of the hydrodynamic function, H(q), collapses into a single master curve.
- This master curve is independent of permeability after appropriate shifting and scaling.
Conclusions:
- Particle permeability is a key factor influencing dynamic properties of colloidal suspensions.
- The observed master curve suggests a universal scaling behavior for the hydrodynamic function of permeable spheres.
- The permeable sphere model captures generic features relevant to real porous colloidal systems.
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