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Plasma nanocoated carbon nanotubes for heat transfer nanofluids
Young Jo Kim1, Hongbin Ma, Qingsong Yu
1Center for Surface Science and Plasma Technology, Department of Mechanical and Aerospace Engineering, University of Missouri, Columbia, MO 65211, USA.
Nanotechnology
|June 30, 2010
Summary
Plasma treatment of carbon nanotubes (CNTs) enhances their dispersion in water, significantly boosting thermal conductivity. This method achieves stable, surfactant-free CNT suspensions with improved heat transfer properties.
Area of Science:
- Materials Science
- Nanotechnology
- Physical Chemistry
Background:
- Carbon nanotubes (CNTs) possess excellent thermal properties but suffer from poor dispersion in base fluids.
- Agglomeration of CNTs limits their effectiveness in heat transfer applications.
- Developing stable CNT suspensions without surfactants is crucial for practical applications.
Purpose of the Study:
- To investigate the effect of plasma treatment on the dispersion and stability of multi-wall carbon nanotubes (CNTs) in water.
- To evaluate the impact of plasma-treated CNTs on the thermal conductivity of water-based nanofluids.
- To confirm surface modifications induced by plasma treatment.
Main Methods:
- Multi-wall carbon nanotubes (CNTs) were subjected to plasma treatment using argon, oxygen, and methane/oxygen mixtures.
- Plasma-treated CNTs were dispersed in water at a concentration of 0.01 vol%.
- Thermal conductivity was measured, and suspension stability was assessed over 5 days.
- Surface characterization was performed using Raman spectroscopy and transmission electron microscopy (TEM).
Main Results:
- Plasma treatment, particularly with nanoscale plasma coatings, significantly improved CNT dispersion and suspension stability in water.
- An initial 25% increase in thermal conductivity was observed with 0.01 vol% plasma-treated CNTs.
- A stabilized 20% increase in thermal conductivity was maintained after 5 days of settling.
- Effective dispersion and enhanced thermal conductivity were achieved without surfactants or dispersing agents.
- Raman spectroscopy confirmed surface modification, and TEM revealed ultra-thin (approx. 2 nm) nanocoatings.
Conclusions:
- Plasma treatment is an effective method for enhancing the dispersion and stability of CNTs in water.
- Plasma-treated CNTs significantly improve the thermal conductivity of water-based nanofluids.
- The developed method offers a surfactant-free approach for creating high-performance thermal fluids.
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