684c Anisotropic Thermal Properties of Carbon Nanotubes: Reaction Rate Enhancements and Effects of Covalent Functionalization

Joel T. Abrahamson1, Nitish Nair1, and Michael S. Strano2. (1) Department of Chemical Engineering, Massachusetts Institute of Technology, Building 66-153, 25 Ames St, Cambridge, MA 02139, (2) 66-566 Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139

We have numerically solved the coupled energy balances for a single-walled carbon nanotube (SWNT) with an annular coating of reactive Zr metal and oxide. In our model, thermal transport in the nanotube accelerates reaction front velocity along the length of the annulus by as much as a factor of 10. This offers a proof-of-concept for one-dimensional anisotropic energetic materials, which could find new applications in inorganic synthesis and novel propellants. Interestingly, interfacial resistance is not the most significant factor limiting the coupling due to the large temperature differences between nanotube and annulus at the reaction front. Transient thermoreflectance (TTR) spectroscopy offers a way to measure thermal conductivity and interfacial resistance in this and other novel nanotube-based materials, leading towards experimental demonstration of this effect. We also use TTR to assess the effects of covalent functionalization on the thermal properties of SWNT materials, arising from changes in the SWNT phonon band structure.

[1] J. T. Abrahamson, N. Nair, M. S. Strano. Nanotechnology. 19, (2008), 195701

[2] P. M. Norris et al. Rev. Sci. Instr. 74, (2003), 400