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How Péclet number affects microstructure and transient cluster aggregation in sedimenting colloidal suspensions
A Moncho-Jordá1, A A Louis, J T Padding
1Biocolloid and Fluid Physics Research Group, Departamento de Física Aplicada, Facultad de Ciencias, Universidad de Granada, Campus Fuentenueva S/N, 18071 Granada, Spain. moncho@ugr.es
The Journal of Chemical Physics
|February 25, 2012
Summary
The Péclet number (Pe) influences colloidal particle sedimentation velocity and cluster behavior. Higher Pe numbers lead to monotonic velocity decrease and reduced cluster formation, shifting behavior from equilibrium-like to non-equilibrium.
Area of Science:
- Colloid Science
- Soft Matter Physics
- Computational Chemistry
Background:
- Colloidal particle sedimentation is influenced by particle interactions and flow conditions.
- Understanding non-equilibrium behavior in colloidal systems is crucial for various applications.
Purpose of the Study:
- To investigate the effect of Péclet number (Pe) on the steady-state sedimentation of colloidal particles with short-ranged attractions.
- To analyze how varying Pe influences sedimentation velocity, particle correlations, and transient cluster dynamics.
Main Methods:
- Hybrid molecular dynamics simulations were employed.
- The study systematically varied the Péclet number and packing fraction (φ).
Main Results:
- Sedimentation velocity showed a non-monotonic dependence on φ at low Pe, transitioning to a monotonic decrease at high Pe.
- Pair correlation functions deviated from equilibrium values as Pe increased.
- Transient clusters were observed, with increased fragmentation and decreased aggregation at higher Pe.
Conclusions:
- The Péclet number significantly alters sedimentation behavior and cluster dynamics in colloidal suspensions.
- The system transitions from equilibrium-like to non-equilibrium behavior with increasing Pe due to the balance of convective and thermal forces.
- Cluster formation probability decreases with increasing Pe, while cluster lifetime remains largely unaffected.
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