Thermal Conductivity Enhancement in Nanofluids Containing Carbon Nanotubes

Nanofluids comprising carbon nanotubes (CNTs) dispersed in conventional heat-transfer liquids have emerged as a frontier in thermal management technology. By integrating high-aspect-ratio CNTs into base fluids such as water, ethylene glycol or oil, researchers aim to surpass the intrinsic thermal conductivity limits of pure liquids. Enhancement arises from the excellent phonon transport along the CNT axis, coupled with percolating networks that promote rapid heat transfer through the fluid. Key factors influencing performance include CNT morphology, concentration, surface chemistry and the efficacy of dispersion methods. Improved thermal conductivity has been reported even at low nanotube loadings (below 1 wt %), while stability against sedimentation and viscosity escalation remain critical challenges. Recent work has examined the role of curved versus straight nanotube geometries, the impact of functional groups and metallic nanoparticle decoration, and the optimisation of sonication, milling and surfactant-assisted protocols. Together, these investigations point towards tailored CNT nanofluids for applications ranging from electronics cooling to solar thermal systems, where compact, efficient heat exchangers and chillers benefit from superior fluid conductance and sustained colloidal stability.

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Thermal Conductivity Enhancement in Nanofluids Containing Carbon Nanotubes publication trend

The graph below shows the total number of articles in thermal conductivity enhancement in nanofluids containing carbon nanotubes across all publications each year (not limited to Nature Index journals).

Technical terms

Nanofluid: A colloidal suspension of nanoparticles in a base fluid, engineered to enhance thermal and rheological properties.

Carbon Nanotube (CNT): Cylindrical carbon structures with diameters in the nanometre range and high aspect ratios, known for exceptional thermal and mechanical characteristics.

Thermal Conductivity Enhancement: The relative increase in a fluid’s ability to conduct heat upon addition of conductive nanoparticles, expressed as a percentage over the base fluid.

Functionalization: A chemical modification of nanoparticle surfaces to introduce specific groups or moieties that improve compatibility with the host fluid and prevent aggregation.

Surfactant: A surface-active agent that adsorbs onto nanoparticle surfaces, lowering interfacial energy to maintain stable dispersions.

References

1. Heat Transfer in Carbon-Nanotube Dispersions: A Simulation Study of the Role of Nanotube Morphology and Connectivity. Molecules (2024).
2. Characterizations of MWCNTs Nanofluids on the Effect of Surface Oxidative Treatments. Nanomaterials (2022).
3. Effects of Functionalization in Different Conditions and Ball Milling on the Dispersion and Thermal and Electrical Conductivity of MWCNTs in Aqueous Solution. Nanomaterials (2021).