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Shear-thickening and entropy-driven reentrance
Mauro Sellitto1, Jorge Kurchan
1Institute for Scientific Interchange, Viale S. Severo 65, 10133 Torino, Italy.
Physical Review Letters
|December 31, 2005
Summary
We found a simple, generic mechanism explaining shear thickening in glassy systems. This mechanism, analogous to entropy-driven phase reentrance, leads to jamming, intermittency, and metastability under stirring.
Area of Science:
- Soft Matter Physics
- Rheology
- Complex Systems
Background:
- Shear thickening is a complex rheological phenomenon observed in various materials.
- Existing models often lack a unified, generic mechanism applicable across different systems.
- Understanding jamming transitions in glassy systems is crucial for predicting material behavior.
Purpose of the Study:
- To introduce a generic mechanism for shear thickening.
- To investigate this mechanism in simple, nonrelaxational mean-field glassy systems.
- To provide a microscopic basis for shear thickening and related phenomena.
Main Methods:
- Implementation of a generic shear thickening mechanism.
- Study of nonrelaxational mean-field glassy models.
- Analysis of dynamical phase diagrams under stirring conditions.
Main Results:
- Observed a dynamical phase diagram with second- and first-order stirring-induced jamming transitions.
- Demonstrated phenomena such as intermittency, metastability, and phase coexistence.
- Found the jammed state to be fragile concerning changes in stirring direction.
- Derived a mode-coupling theory for shear thickening.
Conclusions:
- The proposed generic mechanism effectively explains shear thickening in simple glassy systems.
- The model reproduces experimentally observed behaviors like intermittency and metastability.
- This work offers a direct link between microscopic models and macroscopic rheological observations.
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