A dual-functional composite film with high thermal conductivity and infrared emissivity for passive thermal management

Radiative cooling (RC) technology has attracted significant attention for enabling passive heat dissipation without energy consumption. However, the low thermal conductivity of polymer-based materials poses significant challenges to their practical application in devices with internal heat sources. To address this issue, we developed a dual-functional composite film by embedding a three-dimensional porous copper foam skeleton into a TiO 2 /SiO 2 -filled polydimethylsiloxane (PDMS) matrix. The as-fabricated composite film exhibits a high thermal conductivity of up to ∼ 6.70 W m −1 K −1 while maintaining a high average emissivity( ε ¯ 8-13μm ) of ∼ 0.91 within the atmospheric window (8‒13 µm). Simulated heat dissipation testing revealed that, under nocturnal simulated heat source conditions, the 60 PPI composite film achieved a temperature reduction of approximately 4.16 °C compared to traditional radiative cooling materials. This synergistic design overcomes the critical thermal bottleneck of conventional RC materials, providing a promising pathway for the passive thermal management of high-power-density electronic devices.