Sandwich‐Like Silicone Rubber Composites With Oriented Thermal Conductive Pathways and Flexible Surface Layers for High‐Performance Thermal Management

ABSTRACT Thermal interface materials (TIMs) require both efficient through‐plane heat conduction and low thermal contact resistance at rough interfaces. Herein, a sandwich‐like silicone rubber composite was developed to simultaneously enhance bulk heat transport and interfacial contact. The middle layer contains an oriented silicon carbide nanowire (SiCNW)/MXene network that provides continuous through‐plane heat‐conduction pathways at low filler loading. For the flexible surface layers, liquid metal (LM) was anchored onto caffeic acid‐modified Al 2 O 3 particles to form Al 2 O 3 @LM hybrid fillers, providing both local heat conduction and improved interfacial conformity through their deformability. At SiCNW and MXene contents of 2.56 and 0.12 vol%, respectively, the oriented middle layer achieved a through‐plane thermal conductivity of 3.97 W m −1 K −1 . After introducing the flexible surface layers, the sandwich composite retained 3.73 W m −1 K −1 , while its thermal contact resistance at 10 psi decreased from 1.35 to 0.72 K cm 2 W −1 , corresponding to a 46.7% reduction. The composite also maintained stable thermal transport after 500 compression cycles and 500 heating–cooling cycles, demonstrating good durability under repeated mechanical and thermal loading. LED tests further confirmed enhanced heat dissipation under practical contact conditions. These results demonstrate the effectiveness of the sandwich architecture in balancing thermal transport, interfacial adaptability, and reliability for thermal management.