Plasma-Modified Boron Nitride Nanosheets for High-Performance Aramid-Based Dielectric Films with Enhanced...

Aramid paper, due to its lightweight structure, mechanical strength, and excellent dielectric performance, is widely employed in insulation systems of electronic devices and high-voltage equipment. However, its inherently poor thermal conductivity (λ) restricts its applicability in modern high-power systems with demanding thermal management needs. Additionally, conventional blending approaches often yield poor filler-matrix interfaces, which severely limit the enhancement of λ and simultaneously deteriorate other properties. Herein, a plasma-assisted amino functionalization approach is reported for boron nitride nanosheets to reinforce its interfacial affinity with 1D aramid nanofibers (ANF). Together with Silk Fibroin (SK), serving as a flexible molecular binder, a biomimetic nacre-inspired architecture is achieved through a self-assembly process. The synergistic effect of strong interfacial interactions and a 3D hydrogen bonding network endows the composite films with outstanding thermal conductivity of 13.89 Wm^-1K^-1, excellent tensile strength of 307.08 MPa, as well as superior thermal resistance and long-term operational stability. Moreover, the highly ordered microstructure results in an ultrahigh breakdown strength (up to 430 kVmm^-1) and a low dielectric loss. The findings of this study provide a rational design strategy for multifunctional polymer-based dielectric materials aimed at next-generation high-power electronic devices.