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Published on: January 23, 2018
Reversible temperature regulation of electrical and thermal conductivity using liquid-solid phase transitions
Ruiting Zheng1, Jinwei Gao, Jianjian Wang
1Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
Nature Communications
|April 21, 2011
Summary
Researchers developed a new method to control material conductivity using phase transitions. This technique offers significant changes in electrical and thermal properties for applications like temperature regulation and energy storage.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Chemical Engineering
Background:
- Controlling electrical and thermal conductivity is crucial for advanced applications.
- Existing methods often lack large contrasts or reversibility.
- Temperature-responsive materials are needed for smart systems.
Purpose of the Study:
- To introduce a general strategy for achieving large, reversible contrasts in conductivity.
- To leverage first-order phase transitions in composite materials.
- To demonstrate tunable conductivity for practical applications.
Main Methods:
- Utilizing percolated composite materials with a phase-transitioning component.
- Inducing internal stress during phase transition to modulate contact resistances.
- Testing graphite/hexadecane, graphite/water, and carbon nanotube/hexadecane suspensions.
Main Results:
- Achieved large contrasts in electrical and thermal conductivities at the phase transition temperature.
- Demonstrated a 2-order-of-magnitude change in electrical conductivity for graphite/hexadecane.
- Observed up to a 3.2-fold variation in thermal conductivity near 18 °C.
Conclusions:
- The proposed strategy enables significant, reversible tuning of material conductivity.
- Phase transitions in composite materials offer a versatile route to conductivity control.
- This approach has potential for applications in thermal management, energy storage, and sensing.
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