  The thermal properties of single-walled carbon nanotubes (SWNTs) are of
significant interest, yet their dependence on SWNT chirality has been, until
now, not explored experimentally. Here we used electrical heating and infrared
thermal imaging to simultaneously study thermal and electrical transport in
chirality-sorted SWNT networks. We examined solution processed 90%
semiconducting, 90% metallic, purified unsorted (66% semiconducting), and
as-grown HiPco SWNT films. The thermal conductivities of these films range from
80 to 370 W/m/K but are not controlled by chirality, instead being dependent on
the morphology (i.e. mass and junction density, quasi-alignment) of the
networks. The upper range of the thermal conductivities measured is comparable
to that of the best metals (Cu and Ag) but with over an order of magnitude
lower mass density. This study reveals important factors controlling the
thermal properties of light-weight chirality-sorted SWNT films, for potential
thermal and thermoelectric applications.
