Molecular dynamics study on the influence of size on thermal conductivity of carbon nanotubes with different structures

Abstract

This study employs Molecular dynamics (MD) to systematically elucidate the structure-property relationship between geometric parameters and thermal transport characteristics of two typical chiral CNT (Armchair and Zigzag). The results reveal that the thermal conductivity of CNT is significantly influenced by their structural type, size, and temperature, with distinct behaviors observed for armchair and zigzag. Specifically, armchair exhibit higher thermal conductivity for smaller lengths (<40 nm), with distinct trends observed around a diameter of 2 nm: Below 2 nm, the thermal conductivity increases linearly with diameter. Above 2 nm, structural effects become pronounced, leading to an increase in the thermal conductivity difference between the two structures, accompanied by an oscillatory growth pattern as the diameter increases. For longer lengths (>40 nm), zigzag exhibit higher thermal conductivity. In addition, thermal conductivity decreases with increasing temperature. This study analyzes the heat conduction mechanisms of CNT using key thermal parameters and phonon theory.