One-directional thermal transport in densely aligned single-wall carbon nanotube films

• Published in: Applied physics letters Vol. 115; no. 22
• Main Authors: Yamaguchi, Shingi, Tsunekawa, Issei, Komatsu, Natsumi, Gao, Weilu, Shiga, Takuma, Kodama, Takashi, Kono, Junichiro, Shiomi, Junichiro
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 25.11.2019
• Subjects: Alignment; Anisotropy; Applied physics; Conduction heating; Conductive heat transfer; Conductivity; Heat conductivity; Single wall carbon nanotubes; Temperature dependence; Thermal conductivity; Thermal energy; Thermal resistance; Transport; Vacuum filtration
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.5127209

Individual carbon nanotubes (CNTs) possess extremely high thermal conductivities. However, the thermal conductivities and their anisotropy of macroscopic assemblies of CNTs have so far remained small. Here, we report the results of directional thermal transport measurements on a nearly perfectly aligned CNT film fabricated via controlled vacuum filtration. We found the thermal conductivity to be 43 ± 2.2 W m−1 K−1 with a record-high thermal anisotropy of 500. From the temperature dependence of the thermal conductivity and its agreement with the atomistic phonon transport calculation, we conclude that the effect of intertube thermal resistance on heat conduction in the alignment direction is negligible because of the large contact area between CNTs. These observations thus represent ideal unidirectional thermal transport, i.e., the thermal conductivity of the film is determined solely by that of individual CNTs.