Tuning thermal conductance of CNT interface junction via stretching and atomic bonding

Abstract

In this work, various effects of stretching and bonding strength on the thermal transport at CNT junctions are comprehensively studied by classical molecular dynamics (MD) simulations. The modeling is performed on a typical parallel-aligned junction formed by two single-walled (10, 10) CNTs. The overlap length is the first condition we studied and it is found that thermal conductance is significantly increased from 1.00 to 11.76 nW K−1 with overlap length from 0.982 to 6.877 nm. Surprisingly, the thermal conductance per unit overlap length is increased rather than a constant value. The van der Waals interaction in non-bonded CNTs has a positive correlation on thermal conductance, which means thermal conductance can be effectively enhanced by applied force in the inter-tube direction. In the axial direction, the applied force is an important condition to adjust thermal conductance at bonded junction. Results show that the thermal conductance for overlap length of 1.966 nm can be enhanced from 2.81 to 3.42 nW K−1 at the initial stage because of the combined squeezing force. However, as applied force approaches the breaking value, the atomic bonding at the junction is greatly weakened with a rapidly dropping thermal conductance from 3.42 to 1.88 nW K−1.