A molecular dynamics approach of the role of carbon nanotube diameter on thermal interfacial resistance through vibrational mismatch analysis

Carbon nanotubes (CNT) have been known to increase the heat transfer at the solid-liquid interfaces, but have a limitation due to the thermal interfacial resistance. Vibrational mismatch at the interface leads to this thermal interfacial resistance, which plays an important role in energy transfer at the boundary. Negligible work has been reported on the influence of CNT diameter on the resistance through the vibrational mismatch study. Molecular dynamics simulations have been performed to investigate the effect of single walled armchair CNT diameter on interfacial resistance between CNT and water molecules. This work is an effort to understand the heat transfer phenomenon at the interface of armchair CNT and water molecules. Vibrational mismatch at the interface is quantified by analyzing the vibrational spectra of CNT and water molecules. The thermal interfacial resistance is observed to be relatively higher for the larger diameter nanotube. This is attributed to the higher vibrational mismatch existing for larger diameter CNT due to low overlapping region between vibrational density states of CNT and water molecules. For smaller diameter CNT, the thermal interfacial resistance is low which results in the efficient heat transfer at the interface thus, emphasizing the indispensable role of smaller diameter CNTs in the cooling applications.