カーボンナノチューブ/ポリマー複合材の熱伝導における界面熱抵抗と界面フォノン散乱の影響

概要

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Polymer nanocomposites are one of the most promising applications of carbon nanotubes (CNTs). In order to improve their thermal properties, it is important to understand their heat conduction characteristics from a microscopic viewpoint. In this study, we have investigated the heat conduction of CNT/polyethylene composites by using molecular dynamics simulations. We particularly focused on the thermal boundary conductance across CNT/polyethylene interfaces and thermal conductivity of CNT in polyethylene matrix, which govern the overall thermal conductivity of CNT/polyethylene composites. We found relatively low thermal boundary conductance across CNT/polyethylene interfaces (10 MWm-2K-1) and a moderate but non-negligible thermal conductivity reduction of CNT in polyethylene matrix (22 %). By the mode-dependent phonon transport analysis, the thermal conductivity reduction was identified to be mainly due to scattering of low frequency CNT phonons by polyethylene. The results obtained through an effective medium approximation model give overall thermal conductivity of the CNT/polyethylene composite that is in agreement with experiments.