A two-dimensional finite element model for Cu-CNT composite: The impact of interface resistances on electrical and thermal transports

Copper (Cu)-carbon nanotube (CNT) composites are considered as potential alternatives for pure Cu based on the theoretical predictions of their superior electrical, thermal, and mechanical properties. However, the conductivities of experimentally synthesized Cu-CNT composites rarely exceed those of Cu primarily due to the large inherent interface resistances. Here, this article presents a two-dimensional (2D) finite element model (FEM) which accounts for the interface resistances both at CNT-CNT and Cu-CNT contacts, random distribution of CNTs, and CNT fractions up to 80%. The model predicts that the high concentration of single-walled CNTs in Cu matrix may enhance the composite electrical and thermal conductivity by up-to ∼5 times at 27℃ only when interface resistances are highly regulated below 1 kΩ and 10⁻⁷ m²K/W. The streamlines of electrical current and heat flow reveal that the CNTs serve as an effective conduction medium only with the low levels of interface resistance. This work elucidates the importance of interface resistances for the electrical and thermal transport in Cu-CNT composites.