Aramid Nanofiber‐Based Thermally Conductive Films: Nanofibrillation and Thermal Conductivity Improvement

Aramid nanofiber (ANF), derived from poly‐ p ‐phenylene terephthamide (PPTA) fiber, becomes a rising star in the field of cutting‐edge nanomaterials. Considering its enticing intrinsic thermal conductivity, mechanical robustness and thermal stability stemming from the strong hydrogen‐bonding network constructed by rigid molecular chains, ANF and its thermally conductive composites have garnered tremendous attention. In the past decades, tremendous efforts have been made in the development of ANF‐based thermally conductive composites with path‐breaking thermal conductivity and mechanical properties. Herein, recent advances in nanofibrillation strategies, ANF films with high intrinsic thermal conductivity, and ANF‐based thermally conductive composites are summarized. Multiscale structural optimization associated with various processing methods to ameliorate the intrinsic thermal conductivity of ANF films is highlighted. The unique coupling mode between PPTA molecular chains and thermally conductive fillers as well as their correlations to the thermal conductivity and mechanical performance of composites are thoroughly probed. This review offers a guidance to develop advanced polymer‐based thermally conductive composites for efficient thermal management applications.