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Combining Microfluidics and Microrheology to Determine Rheological Properties of Soft Matter during Repeated Phase Transitions
Published on: April 19, 2018
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Rheological properties vs. local dynamics in model disordered materials at low temperature.
1Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, F-69622, Villeurbanne Cedex, France.
The European Physical Journal. E, Soft Matter
|May 27, 2014
Summary
This study reveals disordered materials exhibit a Herschel-Bulkley rheological response, independent of bond rigidity. Apparent viscosity links to a time scale, suggesting local dynamics influence global mechanical behavior.
Area of Science:
- Rheology
- Materials Science
- Soft Matter Physics
Background:
- Disordered materials exhibit complex mechanical responses under shear.
- Understanding the relationship between local dynamics and macroscopic rheology is crucial.
Purpose of the Study:
- To investigate the low-temperature rheological behavior of sheared model disordered materials.
- To determine the influence of bond rigidity on flow curves and viscosity.
- To develop a model explaining the observed rheological phenomena.
Main Methods:
- Shear rheology experiments at low temperatures.
- Systematic variation of bond rigidity in a model disordered material.
- Analysis of flow curves and apparent viscosity.
- Development of a theoretical model for strain heterogeneity propagation.
Main Results:
- Flow curves consistently follow a Herschel-Bulkley law with an exponent near 0.5, irrespective of bond rigidity.
- Apparent viscosity is directly related to a characteristic time scale (t_rel).
- A model explaining the Herschel-Bulkley exponent through shear rate-dependent heterogeneity size was proposed.
Conclusions:
- The Herschel-Bulkley law is a robust descriptor for the rheology of these disordered materials.
- Local dynamics, captured by t_rel, are strongly coupled to the material's global mechanical response.
- The proposed model provides a mechanistic explanation for the observed shear-thinning behavior.
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