Nacre-inspired hydroxylated BNNS/aramid composite paper with interfacially engineered lamellar networks for efficient thermal conduction

The intrinsically low thermal conductivity of traditional aramid paper hinders its application in next-generation high-power electrical systems. Although incorporating thermally conductive fillers is a common strategy, it often leads to severe filler agglomeration and interfacial incompatibility, thereby compromising the mechanical integrity and dielectric properties of the aramid paper. Herein, hydroxyl-functionalized boron nitride nanosheets (OH-BNNS) were strategically assembled into a biomimetic nacre-like architecture to fabricate thermally conductive aramid composite papers (PPH@B). A multicomponent lamellar architecture was constructed by combining OH-BNNS with PDOPA-modified PMIA chopped fibers (PPMIA-CFs), unmodified PMIA floc fibers (PMIA-FFs), and hydroxyapatite nanowires (HAPNWs), while mica nanosheets were introduced in the PPH@MB counterpart to evaluate the effect of additional insulating platelets on the lamellar network. This structural design uses interfacial engineering to improve the dispersion of OH-BNNS and promote close contact between the nanosheets and the aramid-based framework, thereby supporting the formation of connected in-plane heat-transfer paths in the composite paper. The optimized PPH@B 20 achieves an in-plane thermal conductivity of 5.16 W m − 1 K − 1 while retaining a tensile strength of 68.79 MPa and an electrical breakdown strength of 35.45 kV mm − 1 . When applied to LED devices, PPH@B achieves a significant reduction in operating temperature. PPH@B also exhibits excellent flexibility and dimensional stability, highlighting its broad potential for thermal management of electrical systems and advanced electronic packaging.