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Crystal nucleation of colloidal suspensions under shear
Ronald Blaak1, Stefan Auer, Daan Frenkel
1Institut für Theoretische Physik II, Heinrich-Heine-Universität, Universitätsstrasse 1, D-40225 Düsseldorf, Germany.
Physical Review Letters
|August 25, 2004
Summary
Homogeneous shear flow suppresses crystal nucleation rate and increases critical nucleus size. A modified classical nucleation theory explains these effects, with nuclei orienting tilted to the shear direction.
Area of Science:
- Materials Science
- Physical Chemistry
- Computational Physics
Background:
- Homogeneous crystal nucleation is fundamental to materials processing.
- Understanding external influences like shear flow is crucial for controlling crystallization.
- Classical nucleation theory provides a baseline but may not capture complex flow effects.
Purpose of the Study:
- To investigate the impact of homogeneous shear flow on crystal nucleation.
- To quantify changes in nucleation rate and critical nucleus size under shear.
- To develop a theoretical framework explaining shear-induced nucleation phenomena.
Main Methods:
- Brownian dynamics simulations were employed.
- Umbrella sampling technique was utilized to overcome energy barriers.
- Analysis focused on the nucleation rate and critical nucleus characteristics.
Main Results:
- Homogeneous shear flow significantly suppresses the crystal nucleation rate.
- The size of the critical nucleus increases under shear conditions.
- Observed phenomena are consistent with a phenomenological extension of classical nucleation theory.
- Crystal nuclei exhibit an orientation tilted relative to the shear direction.
Conclusions:
- Shear flow acts as a significant inhibitor of homogeneous crystal nucleation.
- The critical nucleus size is sensitive to applied shear stress.
- Classical nucleation theory can be adapted to incorporate shear effects.
- Nucleus orientation provides insights into the mechanism of shear influence.