A Phase‐Change‐Enabled Thermal Interface Material With the Competitive Thermal Resistance of 0.03°C·cm 2 ·W −1 for Electronic Devices Thermal Management in AI Era

ABSTRACT The pursuit of efficient thermal management for AI electronics devices requires TIMs capable of simultaneously lowering bulk and contact thermal resistance. Herein, we report a phase‐change TIM (PC‐TIM) designed on this principle, synthesized by grafting octadecane onto poly(methylhydrosiloxane) and compounding it with polydimethylsiloxane and aluminum fillers. Owing to structural polar compatibility among the polymer chains, the material achieves exceptional stability with a leakage ratio below 0.3 wt.%, alongside a low thermal resistance of 0.03°C·cm 2 ·W −1— performance that is competitive with leading polymer‐based and commercial TIMs. The outstanding performance is attributed to a multiscale optimization strategy: macroscale reorganization of polymer chains and the filler network reduce bond line thickness; microscale enhancement in compliance ensures conformal contact; and atomic‐scale improvements in wettability and phonon spectrum matching jointly boost cross‐interface heat transfer. The effectiveness of PC‐TIM has been validated in multiple devices, including LEDs, optical modules, and MOSFETs, where it exhibits outstanding heat dissipation performance, superior to the referenced commercial products. Notably, in AI‐oriented GPU tests, the PC‐TIM reduced the operating temperature by an additional 5°C compared to the original TIM while maintaining excellent stability.