Thermal conductance control of non-bonded interaction between loaded halogen molecules and carbon nanotubes: A molecular dynamics study

The performance degradation of highly thermal conductive carbon nanotubes (CNT) after assembly limits the application of CNT materials, which is mainly ascribed to the weakly coupled CNTs interfacial heat transfer. The researchers proposed that the low-frequency vibration molecules loaded between the CNTs could solve this problem. However, although experimentally measured thermal conductivity values have shown the heat transfer enhancement, the enhancement mechanism lacks in-depth exploration. Based on molecular dynamics simulations, this work explored the variation of thermal conductance of CNT loaded with halogen molecules, including iodine chains and bromine molecules, as a function of halogen load amount, initial distribution and constant heating temperature, and explore the mechanism through the vibration density of state, phonon overlap energy and molecule trajectory. The initial distribution gives the halogen molecules different binding forces from neighboring atoms, different temperatures provide energy to halogen molecules for movement or binding force break, and stable position of halogen molecules induces low frequency resonance on specific position and number carbon atoms. This work could provide a theoretical basis for the thermal design and precise thermal control of CNT assembled materials.