Real-Use thermal performance of polymer-based thermal interface materials with engineered filler architectures

The increasing power density of modern electronic systems highlights a critical gap between the intrinsic thermal conductivity of thermal interface materials (TIMs) and their actual performance under realistic operating conditions. This study addresses this challenge by developing thermoplastic polyurethane (TPU)-based TIMs with engineered carbon nanotube (CNT) and hexagonal boron nitride (BN) hybrid filler architectures, guided by a mechanism-driven interfacial heat transport framework. Unlike conventional studies relying on steady-state measurements, the thermal performance of the proposed materials was systematically evaluated under real computer operating conditions, enabling direct correlation between filler architecture and device-level heat dissipation behavior. The TPU composite containing 50%wt CNT exhibited the highest thermal conductivity of 1.718 W/mK while maintaining a low electrical conductivity of 4.20 × 10 −10 S/cm. Meanwhile, the hybrid composite containing 25%wt CNT and 25%wt BN achieved a thermal conductivity of 1.389 W/mK with an ultra-low electrical conductivity of 3.23 × 10 −12 S/cm, demonstrating an effective balance between thermal transport and electrical insulation. Importantly, the materials showed stable thermal performance under sustained and cyclic workloads, withstanding heat fluxes exceeding 3.8 × 10 5 W/m 2 without thermal runaway or interfacial degradation. The results further reveal that the synergistic interaction between 1D CNTs and 2D BN fillers promotes multidirectional phonon transport while suppressing electrical percolation. This work establishes a direct link between microstructural design and real-use performance, providing a scalable and cost-effective strategy for next-generation TIMs beyond conventional silicone-based systems.