Anisotropic epoxy composites with enhanced thermal conductivity via constructing unidirectional porous AlN reinforcements

The ongoing miniaturization and increasing integration density of modern microelectronic devices have made thermal management a critical challenge for sustained performance advancement. While polymer/ceramic composites are commonly used as thermal management materials, their effectiveness is fundamentally limited by discontinuous thermal conductive pathways, resulting in unsatisfied thermal conductivity (TC). Although increasing filler loading can enhance TC, it typically compromises processability and mechanical properties of the composites. To address these limitations, unidirectional porous (UP) AlN ceramics were innovatively fabricated via freeze casting followed by combustion synthesis, which were subsequently incorporated into epoxy matrices. At a AlN loading of 47.5 vol%, the composites achieved the TC_∥ (parallel to the channels) of 10.30 W·m^-1·K^-1 and TC_⊥ (perpendicular to the channels) of 6.03 W·m^-1·K^-1, respectively. Comprehensive evaluations through both experimental CPU cooling tests and finite element simulations verified their superior thermal dissipation capability. The UP AlN reinforcement further enhanced the mechanical properties of the composites and facilitated their long service life. This work presents a scalable and cost-effective material solution for advanced thermal management in high-power microelectronics.