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Cooling Rate Dependent Ellipsometry Measurements to Determine the Dynamics of Thin Glassy Films
Published on: January 26, 2016
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Understanding soft glassy materials using an energy landscape approach.
Hyun Joo Hwang1, Robert A Riggleman1, John C Crocker1
1Department of Chemical and Biomolecular Engineering, University of Pennsylvania, 220 S. 33rd Street, Philadelphia, Pennsylvania 19104-6393, USA.
Nature Materials
|June 21, 2016
Summary
Soft glassy rheology in materials like foams and cells is explained by fractal energy landscapes. This fractal geometry underlies complex behaviors such as power-law rheology and avalanches in soft matter.
Area of Science:
- Soft Matter Physics
- Rheology
- Materials Science
Background:
- Diverse soft materials (e.g., foams, mayonnaise, cells) exhibit similar viscoelastic properties.
- The underlying physical principles of soft glassy rheology remain poorly understood.
Purpose of the Study:
- To investigate the fundamental physical mechanisms behind soft glassy rheology.
- To explain the manifestation of this behavior across different soft materials.
Main Methods:
- Utilized a model soap foam with compressible, size-evolving spherical bubbles.
- Studied foam dynamics as energy minimization-driven downhill motion on a high-dimensional energy landscape.
Main Results:
- Identified fractal geometry in the downhill paths within the energy landscape.
- Linked complex behaviors (power-law rheology, non-diffusive motion, avalanches) to fractal dimension and energy function.
- Demonstrated that emergent fractal geometry explains observed phenomena.
Conclusions:
- Soft glassy rheology in complex fluids may arise from emergent fractal geometry in their energy landscapes.
- The fractal nature of energy landscapes provides a unifying physical explanation for diverse soft material behaviors.
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