Thermally conductive, mechanically strong dielectric film made from aramid nanofiber and edge-hydroxylated boron nitride nanosheet for thermal management applications

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(-1)K(-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 (similar to 0.03), high tensile strength (similar to 88 MPa), and a high decomposition temperature (>510 degrees 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.

Automated summary

A new strategy for preparing thermally conductive films by combining one-dimensional aramid nanofiber with two-dimensional edge-hydroxylated boron nitride nanosheet has been reported. The obtained ANF/OH-BNNS film exhibits ultrahigh in-plane thermal conductivity and excellent thermal properties, mechanical properties, and low dielectric loss. This finding holds great promise for the fabrication and practical application of thermal management materials in high-temperature electronics and devices.