Super-aligned carbon nanotube (CNT) films have intriguing anisotropic thermal transport properties due to the anisotropic nature of individual nanotubes and the important role of nanotube alignment. The exact relation between the alignment and the anisotropic thermal conductivities, however, was not well understood due to the challenges in both the preparation of high-quality super-aligned CNT samples and the thermal characterization of highly anisotropic and porous thin films. Here, super-aligned CNT films with different alignment configurations are fabricated and their anisotropic thermal conductivities are measured using an elliptical-beam approach of time-domain thermoreflectance (TDTR). The results suggest that the alignment configuration can tune the cross-plane thermal conductivity $k_z$ from 6.4 to 1.5 W/(mK), and the in-plane anisotropic ratio from 1.2 to 13.5. This work confirms the important role of CNT alignment in tuning the thermal transport properties of super-aligned CNT films and provides an efficient way to design thermally anisotropic films for thermal management.

由于单个纳米管的各向异性性质和纳米管排列的重要作用，超排列碳纳米管 (CNT) 薄膜具有有趣的各向异性热传输特性。然而，由于制备高质量超排列 CNT 样品和高度各向异性和多孔薄膜的热表征方面的挑战，排列和各向异性热导率之间的确切关系并没有得到很好的理解。在这里，制造了具有不同排列配置的超排列 CNT 薄膜，并使用时域热反射 (TDTR) 的椭圆光束方法测量了它们的各向异性热导率。结果表明对齐配置可以调整跨平面热导率${克}_z$从 6.4 到 1.5 W/(mK)，面内各向异性比从 1.2 到 13.5。这项工作证实了 CNT 排列在调节超排列 CNT 薄膜的热传输特性中的重要作用，并提供了一种设计热各向异性薄膜以进行热管理的有效方法。