Aramid nanofiber supported spherical Al2O3/BN film with high thermal conductivity and outstanding dimensional stability

Polymeric thermal management materials present several advantages that cannot be substituted by metallic or ceramic materials, including easy processing, lightweight characteristics, and low density. However, the unsatisfactory thermal conductivity of polymers limits their effectiveness in dissipating heat during the operation of electrical appliances. This study focuses on the preparation of polymer nanofiber films that exhibit high thermal conductivity and thermal stability through the engineering of flexible aramid nanofibers (ANFs) characterized by a one-dimensional linear structure in conjunction with spherical Al₂O₃/BN particles that possess a rigid structure. The introduction of rigid Al₂O₃/BN particles mitigated the internal agglomeration and entanglement of ANFs, thereby promoting a more organized arrangement of the polymer molecular chains, which resulted in a 54.87 % enhancement in the in-plane thermal conductivity. Furthermore, the favorable interfacial interactions between the stacked ANFs and the Al₂O₃/BNs further promoted efficient phonon transfer. Additionally, the superior thermal and dimensional stability of the polymer nanofiber films enables effective thermal management of electronic devices operating within a temperature range of 20–120 °C.