Fluctuations in dispersion rheology
Chow1
1Xerox Research and Technology, 800 Phillips Road, 0114-39D, Webster, New York 14580, USA.
Summary
This study presents a new model for complex dispersions, explaining how shear viscosity changes with concentration and temperature. It reveals insights into shear thinning and viscosity divergence near critical temperatures.
Area of Science:
- Rheology of complex fluids
- Condensed matter physics
Background:
- Complex dispersions exhibit unique rheological properties.
- Understanding shear viscosity and modulus is crucial for material science applications.
Purpose of the Study:
- To develop an experimentally verified model for effective shear viscosity and modulus.
- To describe the behavior of complex dispersions concerning concentration, frequency, and temperature.
Main Methods:
- Utilizing mesoscopic fluctuations of excess density.
- Employing stochastic differential equations for zero-shear viscosity derivation.
- Applying anomalous diffusion equations to determine shear-thinning behavior.
Main Results:
- A model showing large viscosity enhancement across various concentrations.
- Identification of shear-thinning exponent (1>beta>1/2) linked to fractal structure.
- Derivation of shear viscosity divergence near critical temperature as a dynamic critical phenomenon.
Conclusions:
- The developed model accurately describes complex dispersion rheology.
- The study links macroscopic rheological properties to microscopic structural characteristics.
- Findings provide a framework for understanding critical phenomena in complex fluids.
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