Thermal conductivity and interfacial resistance in single-wall carbon nanotube epoxy composites

We report thermal conductivity measurements of purified single-wall carbon nanotube (SWNT) epoxy composites prepared using suspensions of SWNTs in N-N-Dimethylformamide (DMF) and surfactant stabilized aqueous SWNT suspensions. Thermal conductivity enhancement is observed in both types of composites. DMF-processed composites show an advantage at SWNT volume fractions between ϕ ∼ 0.001 to 0.005. Surfactant processed samples, however, permit greater SWNT loading and exhibit larger overall enhancement ( 64 ± 9 ) % at ϕ ∼ 0.1 . The enhancement differences are attributed to a ten-fold larger SWNT/solid-composite interfacial thermal resistance in the surfactant-processed composites compared to DMF-processed composites. The interfacial resistance is extracted from the volume fraction dependence of the thermal conductivity data using effective medium theory. [ C. W. Nan , G. Liu , Y. Lin , and M. Li , Appl. Phys. Lett. 85 , 3549 ( 2004 ) ].