Dependence of Thermal Conductivity of Carbon Nanopeapods on Filling Ratios of Fullerene Molecules

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• 作者：Liu Cui ; Yanhui Feng ; Xinxin Zhang
• 刊名：Journal of Physical Chemistry A
• 出版年：2015
• 出版时间：November 12, 2015
• 年：2015
• 卷：119
• 期：45
• 页码：11226-11232
• 全文大小：473K
• ISSN：1520-5215

文摘

Focusing on carbon nanopeapods (CNPs), i.e., carbon nanotubes (CNTs) filled with fullerene C₆₀ molecules, the thermal conductivity and its dependence on the filling ratio of C₆₀ molecules have been investigated by equilibrium molecular dynamics simulations. It turns out that the CNP thermal conductivity increases first, reaches its maximum value at filling ratio of 50%, and then decreases with increasing filling ratio. The heat transfer mechanisms were analyzed by the motion of C₆₀ molecules, the mass transfer contribution, the phonon vibrational density of states, and the relative contributions of tube and C₆₀ molecules to the total heat flux. The mass transfer in CNPs is mainly attributed to the rotational and translational motion of C₆₀ molecules in tubes. As the filling ratio is larger than 50%, the axially translational motion of C₆₀ molecules gets more and more restricted with increasing filling ratio. For either the mass transfer contribution to heat transfer or the phonon coupling between the tube wall and C₆₀, the peaking behavior occurs at a filling ratio of 50%, which confirms the corresponding maximum thermal conductivity of CNP. With the filling ratio increasing, the dominating contribution to heat transfer changes from tube-wall atoms to fullerene atoms. Their relative contributions almost keep stable when the filling ratio is larger than 50% until it reaches 100%, where the contribution from fullerene atoms suddenly drops because of strong confinement of translational motion of C₆₀ molecules. This work may offer valuable routes for probing heat transport in CNT hybrid structures, and possible device applications.