Preparation of Copper‐Supported Hexagonal Boron Nitride Polydimethylsiloxane Thermal Conductive Gasket

With the increasing complexity of thermal management requirements for high‐power and precision systems, the development of thermal conductive pads is shifting from merely pursuing high thermal conductivity to also taking into account excellent flexibility. Polydimethylsiloxane (PDMS) is an ideal base material for thermal pads due to its excellent elasticity, wide temperature stability, and electrical insulation properties. However, its inherent thermal conductivity is low, and it requires the addition of high thermal conductivity fillers for enhancement. This paper uses polydopamine (PDA) to functionalize the surface of hexagonal boron nitride (h‐BN), yielding h‐BN@PDA. Then, using the phenolic groups on the PDA layer as binding sites, copper (Cu) particles were deposited in situ through chemical reduction to prepare the h‐BN@PDA‐Cu composite filler. Subsequently, the filler was mixed into the PDMS matrix to prepare the PDMS composite material, and the properties were systematically studied. As a result, the composite containing 20 wt% h‐BN@PDA demonstrated a thermal conductivity of 0.336 W/(m·K). The in situ formed Cu particles further built additional metal thermal conductive bridges between the fillers, and the thermal conductivity of h‐BN@PDA‐Cu/PDMS composite material reached 0.342 W/(m·K) while maintaining good flexibility and electrical insulation at the same filler content. This research provides effective approaches for the development of thermal conductive pads that possess high thermal conductivity, high flexibility, and reliability.