Shanghai Institute of Applied Mathematics and Mechanics, Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, Shanghai 200072, People's Republic of China.
Nanoscale. 2018 Oct 4;10(38):18249-18256. doi: 10.1039/c8nr05188g.
Fullerene encapsulation has been proven to be a powerful approach to enhance the mechanical and electronic properties of single-walled carbon nanotubes (SWCNTs). However, some discrepancies emerge in recent studies of the fullerene encapsulation effect on the thermal conductivity of SWCNTs. More specifically, most previous theoretical studies predicted slight enhancement in the thermal conductivity, but the recent experiment by Kodama et al. (Nat. Mat.16, 892, 2017) observed a clear reduction in the thermal conductivity of SWCNTs by fullerene encapsulation. We perform molecular dynamics simulations to revisit this issue, by comparatively investigating the thermal conductivity of the SWCNT (n, n) and the corresponding peapod (n, n) with n = 8, 9, 10, and 11. We find that the encapsulation can reduce the thermal conductivity of narrower SWCNTs with n = 8 and 9, but it can slightly enhance the thermal conductivity of thicker SWCNTs with n = 10 and 11. The underlying mechanisms for these opposite effects are explored by analyzing the encapsulation induced structural deformation and the variation in the phonon dispersion of the SWCNT. We illustrate that the reduction effect observed in the recent experiment is related to the mechanism for reduction of the thermal conductivity for narrower SWCNTs here.
富勒烯封装已被证明是增强单壁碳纳米管（SWCNT）机械和电子性能的有效方法。然而，最近关于富勒烯封装对 SWCNT 热导率影响的研究出现了一些差异。更具体地说，大多数先前的理论研究预测热导率略有增强，但 Kodama 等人最近的实验（Nat. Mat.16, 892, 2017）观察到富勒烯封装明显降低了 SWCNT 的热导率。我们通过比较研究 SWCNT（n，n）和相应的豆荚（n，n）的热导率来重新审视这个问题，其中 n = 8、9、10 和 11。我们发现封装可以降低 n = 8 和 9 的较窄 SWCNT 的热导率，但可以略微提高 n = 10 和 11 的较厚 SWCNT 的热导率。通过分析封装引起的结构变形和 SWCNT 声子色散的变化，探讨了这些相反效果的潜在机制。我们说明，最近实验中观察到的降低效果与这里较窄 SWCNT 热导率降低的机制有关。
