Magnetic‐Field‐Induced Three‐Dimensional Networks to Enhance the Thermal Conductivity for Polydimethylsiloxane‐Based Thermal Interface Materials

ABSTRACT The rapid advancement of miniaturized, high‐power‐density electronics demands thermal interface materials (TIMs) with exceptional heat dissipation capabilities, mechanical flexibility, and electrical insulation. This study presents a novel strategy for fabricating magnetically responsive boron nitride‐iron oxide/polydimethylsiloxane (BN‐Fe ₃ O ₄ /PDMS) TIMs with vertically aligned architectures for high‐performance thermal management. Hydroxyl‐functionalized BN nanosheets were hybridized with Fe ₃ O ₄ nanoparticles via in situ coprecipitation, enabling magnetic field‐assisted alignment within PDMS to construct low‐tortuosity thermal pathways. The optimized BN‐Fe ₃ O ₄ /PDMS TIMs achieved a through‐plane thermal conductivity of 3.65 W m ⁻¹ K ⁻¹ at 40 wt% filler loading—a 15‐fold enhancement over pristine PDMS—while maintaining electrical insulation of 3.41 × 10 ¹⁴ Ω cm and tensile strength of 2.71 MPa. Finite element simulations and experimental validation on LED modules demonstrated superior heat dissipation, with a surface temperature reduction of 11.6°C compared to conventional TIMs. The synergistic effects of interfacial FeOB/N bonding, reduced thermal resistance of 1.0 × 10 ⁻⁶ m ² K W ⁻¹ , and vertically aligned networks were systematically validated through Foygel modeling, spectroscopic analyses, and molecular dynamics simulations. This work establishes a scalable paradigm for designing high‐performance TIMs that address the critical challenges of heat accumulation in next‐generation electronics.