Thermal transport across carbon nanotubes connected by molecular linkers

Nonequilibrium molecular dynamics is applied to investigate thermal transport across two CNTs connected longitudinally by molecular linkers, which is a basic building-block for CNT network structures. We show the effect of different numbers, monomer types, and lengths of molecular linkers on the interfacial thermal conductance between CNTs and molecular linkers. We also analyze the density of vibrational normal modes to further understand the interfacial thermal conductance between different molecular linkers and CNTs. For most of the molecular linker type we simulated, the interfacial thermal conductance decreases with the increasing chain length. We find that aromatic-backbone structures are better than aliphatic-backbone structures to obtain higher interfacial thermal conductance with CNTs. Incorporating double bonds, oxygen atoms and amide groups into polymer chains shifts or redistributes of the density of vibrational normal modes, which in turn tunes the interfacial thermal conductance of molecular linker with CNTs. These results provide guidance for choosing molecular linkers to build up large-scale CNT-based network structures with tunable thermal properties.