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Cooling Rate Dependent Ellipsometry Measurements to Determine the Dynamics of Thin Glassy Films
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Cooling-rate induced softening in a colloidal glass
Yunzhuo Lu1, Zhihua Zhang2, Xing Lu2
1School of Materials Science and Engineering, Dalian Jiaotong University, Dalian, 116028, People's Republic of China. yunzhuohit@gmail.com.
Scientific Reports
|December 6, 2017
Summary
Amorphous solids soften with faster cooling rates due to fewer immobile particles forming. This study reveals the dynamic mechanisms behind cooling-rate-induced softening in colloidal glasses, impacting mechanical performance control.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Soft Matter Physics
Background:
- Amorphous solids exhibit unique mechanical properties distinct from crystalline solids.
- Understanding the influence of cooling rates on amorphous solid properties is crucial for material design.
- The dynamic mechanisms behind cooling-rate-induced softening remain largely unexplored.
Purpose of the Study:
- To elucidate the underlying mechanisms of cooling-rate-induced softening in amorphous solids.
- To investigate the role of particle dynamics in the mechanical behavior of colloidal glasses.
- To establish a link between cooling rates, particle immobilization, and shear modulus.
Main Methods:
- Utilized a colloidal glass as a model system for direct study.
- Employed shear modulus measurements to quantify stress-bearing properties.
- Analyzed the population of immobile particles as a function of cooling rate.
Main Results:
- Demonstrated that amorphous solids soften when vitrified at higher cooling rates.
- Identified space-spanning immobile particles as the primary contributors to shear modulus.
- Observed that higher cooling rates lead to fewer immobile particles, causing softening.
Conclusions:
- The number of immobile particles, influenced by cooling rate, dictates the shear modulus of amorphous solids.
- Faster cooling rates result in fewer immobile particles and consequently, a softer material.
- This finding provides a dynamic basis for controlling the mechanical performance of amorphous solids.
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