Molecular dynamics study on thermal transport at carbon nanotube interface junctions: Effects of mechanical force and chemical functionalization

Classical molecular dynamics (MD) simulations are performed in this work to investigate the interfacial thermal transport across stacked carbon nanotube (CNT) junctions. Various approaches are implemented to increase the thermal conductance (G) between CNTs. Effects of crossing angle, contact area, bonding strength, external force and hydrocarbon functionalization on G are investigated. A remarkably increase of thermal conductance is achieved by connecting two CNTs with hydrocarbon chain linkers CH2. The predicted G changes from 229 pW/K without linkers to 4901 pW/K with an optimized linker number, which increases by a factor of 20. Meanwhile, thermal conductance is found to increase monotonically with contact area but decrease inversely with crossing angle. The van der Waals (vdW) bonding strength has similar effects with applied external force on thermal conductance, both of which facilitate the interfacial thermal transport by enhancing the contact pressures. Synthesized relationship of internal coupling strength, external force and final separation distance between CNTs is explored to illustrate the variation of thermal conductance and intermolecular potential energy.