The specific heat and effective thermal conductivity of composites containing single-wall and multi-wall carbon nanotubes

• Published in: Nanotechnology Vol. 20; no. 24; p. 245705
• Main Authors: Pradhan, N R, Duan, H, Liang, J, Iannacchione, G S
• Format: Journal Article
• Language: English
• Published: England 17-06-2009
• Subjects: Calorimetry - methods; Manufactured Materials - analysis; Materials Testing - methods; Nanotubes, Carbon - chemistry; Nanotubes, Carbon - ultrastructure; Thermal Conductivity
• ISSN: 1361-6528
• DOI: 10.1088/0957-4484/20/24/245705

We present a study of the specific heat and effective thermal conductivity in anisotropic and randomly oriented multi-wall carbon nanotube (MWCNT) and randomly oriented single-wall carbon nanotube (SWCNT) composites from 300 to 400 K. Measurements on randomly oriented MWCNTs and SWCNTs were made by depositing a thin film of CNTs within a calorimetric cell. Anisotropic measurements were made on MWCNTs grown inside the highly ordered, densely packed nanochannels of anodic aluminum oxide. The specific heat of randomly oriented MWCNTs and SWCNTs showed similar behavior to the specific heat of bulk graphite powder. However, the specific heat of aligned MWCNTs is smaller and has weaker temperature dependence than that of the bulk above room temperature. The effective thermal conductivity of randomly oriented MWCNTs and SWCNTs is similar to that of powder graphite, exhibiting a maximum value near 364 K indicating the onset of phonon-phonon scattering. The effective thermal conductivity of the anisotropic MWCNTs increased smoothly with increasing temperature and is indicative of the one-dimensional nature of the heat flow.