Synchronous repair of intrinsic thermal conductivity and mechanical performance of aramid nanofiber films through hydrogen-bonding reconstruction

Abstract

Lightweight polymer-based composites with high thermal conductivity and mechanical robustness are highly desirable for high-efficiency thermal management in electronics. Herein, a thermal annealing-directed molecular engineering strategy is developed to precisely reconfigure the chain conformation and reconstruct the hydrogen-bonding network in aramid nanofiber (ANF) films. Moderate annealing at 200 °C induces the generation of ordered molecular structures and the reconstruction of hydrogen-bonding networks in the ANF film, leading to a substantial increase in its intrinsic thermal conductivity up to 6.16 W m⁻¹ K⁻¹ (a 45.3% enhancement relative to the unannealed film), along with an improved tensile strength of 262.9 MPa. On this basis, highly oriented graphite microplatelets (GMPs) with a large aspect ratio are incorporated to form a synergistic thermally conductive architecture. The improved π–π interactions between the matrix with ordered molecular chain conformation and GMPs significantly contribute to enhancing interfacial phonon coupling and constructing continuous thermal transfer pathways. Thus, the annealed ANF/GMP composite film delivers an exceptional in-plane thermal conductivity of 68.06 W m⁻¹ K⁻¹ while maintaining a mechanical strength of 165.0 MPa. By integrating molecular-scale structural regulation with multiscale synergistic design, this study offers a new avenue for the development of high-performance intrinsically thermally conductive polymers and their composites.