Revealing the in-plane thermal transport disparities between single-walled circular and collapsed carbon nanotubes

In this work, we investigate the in-plane thermal transport disparities between single-walled circular and collapsed carbon nanotubes (CNTs), with a focus on temperature effects and Stone–Wales (SW) defects. Using nonequilibrium molecular dynamics simulations, we reveal that collapsed CNTs exhibit significantly lower thermal conductivity than circular CNTs due to enhanced phonon scattering and thermal disturbances. A dominoes-like reversible transformation is observed in collapsed CNTs at high temperatures (>800 K), while high SW defect densities (>4.0%) induce an irreversible transformation into circular configurations for smaller-diameter collapsed CNTs. Thermal conductivity decreases with increasing temperature and SW density, particularly in smaller-diameter collapsed CNTs with reduced van der Waals adhesion and enhanced phonon–phonon scattering. These findings provide insights into tunable thermal transport in CNTs, offering potential applications in thermoelectric devices and nanoscale thermal management.