ABSTRACT

Polymer-based dielectric films with desirable heat dissipation property hold great promise as thermal management materials in advanced electronics and high power devices. Herein, we report a new strategy for preparing thermally conductive films by synergistically combining one-dimensional (1D) aramid nanofiber (ANF) with 2D edge-hydroxylated boron nitride nanosheet (OH-BNNS) via a vacuum-assisted self-assembly technique. The obtained ANF/OH-BNNS film exhibits an ultrahigh in-plane thermal conductivity of 32.3 W m⁻¹K⁻¹ at 40 wt% BNNS-OH loading, which is 3530% greater than that of the pure ANF film. The excellent thermal conductivity results from the special ‘brick-and-mortar’ layered structure of ANF/OH-BNNS, in which the increased contacting and overlapping of OH-BNNS promotes the formation of the thermal conduction pathways. In addition, the rigid ANFs act as bridges linking OH-BNNS by favorable hydrogen bonding interactions, which efficiently enhance phonon propagation and stress transfer in the film. Moreover, the ANF/OH-BNNS film simultaneously shows low dielectric loss (~0.03), high tensile strength (~88 MPa), and a high decomposition temperature (>510 °C). We believe that these findings are of great importance for the fabrication and practical application of thermal management materials in high-temperature electronics and devices.

摘要

具有理想散热性能的聚合物介电薄膜在先进电子产品和高功率设备中作为热管理材料具有广阔的前景。在此，我们报告了一种通过真空辅助自组装技术将一维 (1D) 芳纶纳米纤维 (ANF) 与二维边缘羟基化氮化硼纳米片 (OH-BNNS) 协同结合来制备导热薄膜的新策略。获得的ANF/OH-BNNS薄膜表现出32.3 W m ^-1 K ^-1的超高面内热导率在 40 wt% BNNS-OH 负载下，比纯 ANF 薄膜高 3530%。ANF/OH-BNNS 特殊的“实体”层状结构导致了优异的导热性，其中 OH-BNNS 的接触和重叠的增加促进了热传导路径的形成。此外，刚性 ANF 通过有利的氢键相互作用充当连接 OH-BNNS 的桥梁，这有效地增强了膜中的声子传播和应力传递。此外，ANF/OH-BNNS 薄膜同时表现出低介电损耗 (~0.03)、高拉伸强度 (~88 MPa) 和高分解温度 (>510 °C)。我们相信这些发现对于高温电子和设备中热管理材料的制造和实际应用具有重要意义。