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Force-driven reversible liquid-gas phase transition mediated by elastic nanosponges
Keita Nomura1, Hirotomo Nishihara2, Masanori Yamamoto1
1Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, 980-8577, Japan.
Nature Communications
|June 19, 2019
Summary
Graphene nanosponges enable a novel force-driven liquid-gas phase transition for efficient heat management. This mechanism offers potential for high-performance cooling systems using green refrigerants.
Area of Science:
- Materials Science
- Nanotechnology
- Thermodynamics
Background:
- Nanoporous materials exhibit unique physicochemical properties due to confined spaces.
- Most nanoporous materials are rigid, limiting their applications.
- Graphene-based nanoporous materials offer significant elasticity, acting as nanosponges.
Purpose of the Study:
- To demonstrate a force-driven liquid-gas phase transition mediated by graphene nanosponges.
- To explore the potential of this phenomenon for high-efficiency heat management.
- To investigate the application of this mechanism with green refrigerants.
Main Methods:
- Utilized graphene-based nanosponges with significant elasticity.
- Applied mechanical compression and free-expansion to induce phase transitions.
- Investigated the thermodynamic effects of compression (heating) and expansion (cooling).
Main Results:
- Demonstrated a force-driven liquid-gas phase transition in guest molecules within nanosponges.
- Observed cooling upon evaporation during free-expansion and heating upon condensation during compression.
- Achieved a latent heat of at least 192 kJ/kg for refrigerants like H2O and alcohols.
- Showcased potential for high coefficients of performance in cooling systems.
Conclusions:
- Graphene nanosponges can mediate a force-driven liquid-gas phase transition for heat management.
- The observed cooling and heating effects are opposite to those in shape-memory metals.
- This mechanism is applicable to green refrigerants and offers potential for efficient cooling systems.
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