The arrangement of anisotropic dielectric fillers in polymer matrix can lead to a significant enhancement of dielectric properties along a specific direction, enabling the rapid development of integrated circuits and high-performance microelectronic devices. In this work, magnetic barium titanate nanofibers/polyimide composite films (mBT NFs/PI) with vertically oriented structures were constructed with the assistant of magnetic field. The dielectric constant was significantly increased from 20.8 to 39.1 at a filler content of 30 wt%, as compared to the randomly aligned films. However, the breakdown strength was affected. Addressing this issue, an optimized core-shell structure was fabricated by introducing insulated and thermo-conductive boron nitride (BN) “shell” on the surface of mBT NFs by coaxial electrospinning. The obtained mBT@BN/PI nanocomposite exhibits improved thermal conductivity and breakdown strength, while maintaining a high dielectric constant. This work highlights an effective strategy to achieve excellent dielectric properties and thermal conductivity for high-temperature dielectric capacitor materials.

中文翻译：

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通过混合 BaTiO3 纳米纤维垂直排列的高介电性能和导热介电复合膜

各向异性介电填料在聚合物基体中的排列可以导致介电性能沿特定方向显着增强，从而促进集成电路和高性能微电子器件的快速发展。本工作在磁场的辅助下构建了具有垂直取向结构的磁性钛酸钡纳米纤维/聚酰亚胺复合薄膜（mBT NFs/PI）。与随机排列的薄膜相比，填料含量为 30 wt% 时介电常数从 20.8 显着增加到 39.1。然而，击穿强度受到影响。为了解决这个问题，通过同轴静电纺丝在 mBT NF 表面引入绝缘导热氮化硼（BN）“壳”，制备了优化的核壳结构。所得的mBT@BN/PI纳米复合材料表现出改善的导热性和击穿强度，同时保持高介电常数。这项工作突出了一种有效策略，可以使高温介电电容器材料实现优异的介电性能和导热性。