Dopamine Functionalized BNNS/PAN Core-Shell Nanofiber Membrane with High Thermal Conductivity and Excellent Dielectric Properties

As the power density of miniaturized electronic devices continues to increase, the development of multifunctional thermal management composites that combine excellent thermal conductivity with low dielectric loss has emerged as a critical challenge in addressing the heat dissipation limitations. However, uneven filler dispersion and interfacial phonon scattering and polarization loss in conventional composites severely limit the synergistic optimization of comprehensive performance. In this work, core-shell structured polyacrylonitrile (PAN) with dopamine-modified boron nitride nanosheets (PBN) interconnected to form a thermally conductive network were innovatively constructed by coaxial electrospinning and hot-pressing process design strategies, the final in-plane orientation is achieved through the process of hot-pressing. The incorporation of 10wt% PBN loading resulted in a substantial enhancement in thermal conductivity. The in-plane thermal conductivity of the composite was enhanced to 6.99 W.m -1 .K -1 , representing an increase of 1377.7% over neat PAN, and the out-of-plane thermal conductivity was as high as 0.387 W.m -1 .K -1 , an increase of 674% over the neat PAN film. Excellent electrical insulation (volume resistivity =6.04×10 14 Ω.cm) with low dielectric properties (ε=1.89 at 1 kHz, tanδ=0.012) is maintained at the same time. The material demonstrates considerable potential for application in scenarios such as chip heat dissipation and flexible printed circuit boards, thereby providing innovative solutions for the thermal design of next generation, highly reliable electronic devices.