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Many-body effects for critical Casimir forces
T G Mattos1, L Harnau, S Dietrich
1Max-Planck-Institut für Intelligente Systeme, Heisenbergstr. 3, D-70569 Stuttgart, Germany. tgmattos@is.mpg.de
The Journal of Chemical Physics
|March 1, 2013
Summary
Critical Casimir forces between colloids in liquid mixtures are investigated. Many-body forces significantly influence these interactions, especially at close distances and near critical temperatures, reaching up to 25% of the total force.
Area of Science:
- Physics
- Physical Chemistry
- Soft Matter Physics
Background:
- Critical Casimir forces arise from fluctuations in critical fluid mixtures.
- These forces are significant for colloidal systems near phase transitions.
Purpose of the Study:
- To calculate scaling functions for critical Casimir forces.
- To analyze normal and lateral forces on colloids near a substrate.
- To quantify many-body contributions to these forces.
Main Methods:
- Mean-field theory calculations.
- Analysis of geometrical arrangements and boundary conditions.
- Subtraction of pairwise forces to isolate many-body effects.
Main Results:
- Observed sign changes in critical Casimir forces with varying colloid position or temperature.
- Identified pronounced many-body contributions at small colloid-colloid and colloid-substrate distances.
- Quantified many-body forces up to 25% of the total force near criticality.
Conclusions:
- Many-body forces play a crucial role in colloidal systems within critical fluids.
- Understanding these forces is essential for predicting colloidal behavior near phase transitions.
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