Polymer‐based thermal management materials have many irreplaceable advantages not found in metals or ceramics, such as easy processing, low density, and excellent flexibility. However, their limited thermal conductivity and unsatisfactory resistance to elevated temperatures (<200 °C) still prevent effective heat dissipation during applications with high‐temperature conditions or powerful operation. Therefore, herein highly thermoconductive and thermostable polymer nanocomposite films prepared by engineering 1D aramid nanofiber (ANF) with worm‐like microscopic morphologies into rigid rod‐like structures with 2D boron nitride nanosheets (BNNS) are reported. With no coils or entanglements, the rigid polymer chain enables a well‐packed crystalline structure resulting in a 20‐fold (or greater) increase in axial thermal conductivity. Additionally, strong interfacial interactions between the weaved ANF rod and the stacked BNNS facilitate efficient heat flux through the 1D/2D configuration. Hence, unprecedented in‐plane thermal conductivities as high as 46.7 W m⁻¹ K⁻¹ can be achieved at only 30 wt% BNNS loading, a value of 137% greater than that of a worm‐like ANF/BNNS counterpart. Moreover, the thermally stable nanocomposite films with light weight (28.9 W m⁻¹ K⁻¹/10³ (kg m⁻³)) and high strength (>100 MPa, 450 °C) enable effective thermal management for microelectrodes operating at temperatures beyond 200 °C.

中文翻译：

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通过工程1D刚性棒状芳族聚酰胺纳米纤维/ 2D氮化硼纳米片制成的高导热，热稳定和超柔韧性薄膜

聚合物基热管理材料具有金属或陶瓷没有的许多不可替代的优势，例如易于加工，低密度和出色的柔韧性。但是，它们的有限的导热性和对高温（<200°C）的令人满意的耐受性仍然阻止了在高温条件下或强力运行的应用中的有效散热。因此，本文报道了通过将具有蠕虫状微观形态的一维芳族聚酰胺纳米纤维（ANF）工程化为具有二维氮化硼纳米片（BNNS）的刚性棒状结构而制备的高导热性和热稳定性聚合物纳米复合膜。在没有线圈或缠结的情况下，刚性聚合物链可以使晶体结构排列得井井有条，从而使轴向导热率提高20倍（或更多）。另外，编织的ANF杆和堆叠的BNNS之间的强界面相互作用有助于通过1D / 2D配置实现有效的热通量。因此，前所未有的面内热导率高达46.7 W m在仅30 wt％的BNNS负载下可以实现^-1 K ^-1，该值比蠕虫状ANF / BNNS同类值大137％。此外，具有重量轻（28.9 W m ^-1 K ^-1 / 10 ³（kg m ^-3））和高强度（> 100 MPa，450°C）的热稳定纳米复合膜可对在一定温度下运行的微电极进行有效的热管理超过200°C。