Efficient thermal conduction in polydimethylsiloxane-based thermal interface materials achieved through amide-bonded BNNS–rGO synergistic network

Polydimethylsiloxane (PDMS) is a prevalent polymeric matrix employed in thermal interface materials (TIMs) for modern electronic devices. Although incorporating thermally conductive fillers enhances its heat dissipation capacity, excessive filler loading compromises mechanical flexibility, thereby constraining its practical application. In this work, we design a hybrid filler by covalently linking boron nitride nanosheets (BNNS) and reduced graphene oxide (rGO) through strong amide bonds, forming a highly thermally conductive BNNS-rGO hybrid filler. This amide bonding substantially reduces interfacial thermal resistance from 2.11 × 10−8 to 0.75 × 10−8 m2 K W−1. Meanwhile, an alternating electric field is adopted to align the fillers, extending thermal conduction pathways and enabling the formation of an ordered, synergistic hybrid network. Cross-sectional scanning electron microscopy reveals the formation of an extended, vertically oriented filler network that enables a thermal conductivity 250% of that of pristine PDMS at only 5 wt. % filler content, with the thermal conductivity enhancement factor reaching 810% of that of BNNS/PDMS. Molecular dynamics simulations reveal that amide bonding improves the matching of phonon vibrational modes across the interface, thereby demonstrating its effectiveness in facilitating phonon transport. This strategy provides a viable approach for developing highly thermally conductive, electrically insulating TIMs at low filler loadings.