Experimental and computational study of h-boron nitride@aramid nanofiber fibers for rapid thermal transfer in wearable thermal management

Thermal garment technologies offer a promising approach to reduce building energy consumption by creating adjustable localized thermal environments around the human body. Although recently developed composite fibers exhibit enhanced thermal conductivity through the incorporation of thermally conductive nanomaterials, their mechanical properties are often compromised at high nanomaterial loadings. This trade-off is primarily attributed to inefficient interfacial force transfer between the nanomaterials and the polymer matrix. To overcome this challenge, we developed h -boron nitride@aramid nanofiber (BN@ANF) coaxial fibers with BN content in the core layer reaching up to 90 wt%. The core–shell volume ratio was precisely controlled by tuning extrusion and drawing rates. The ANF shell provides mechanical reinforcement and BN-90@ANF fibers drawn at a ratio of 2.0 exhibit a tensile strength of 162.5 MPa and a Young's modulus of 4.51 GPa. Both experimental and theoretical analyses reveal that the heat transfer distance of the coaxial fiber is over 10 times longer than that of pure ANF fibers, attributing to continuous phonon transport pathways formed by aligned BN sheets in the core. Experimental data is excellent matching that of computational study and this confirms the thermal conductivity of 38 m −1 K −1 for BN-90@ANF fiber. This work demonstrates a scalable strategy for producing high-performance thermally conductive fibers and offers new insights into composite fiber architecture design for advanced thermal management textiles.