Customized low heat resistance interfacial structure endowing multifunctional composite with excellent thermal conductivity

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Multifunctional polymer-based thermal management composites are essential for the long-term normal service of modern electronic devices. However, multi-position interfacial thermal resistance attributed to the difference in the phase structure significantly limits the full performance of the composite. Herein, based on the molecular structure of a composite formed by boron nitride nanosheets (BNNSs) and aramid nanofibers (ANF), sulfonated ionic liquid (s-IL) was selected by DFT calculation to establish a multiple non-covalent bonding interface structure that comprehensively improves the performance, especially heat transfer. Depending on the functionalization of s-IL, the interface structures of cation-π and OH⋯π constructed between BNNSs and the OH⋯O interaction built between BNNSs and ANF gives the composites a thermal conductivity of up to 23 W/m K−1. In addition, the tensile strength, limiting oxygen index, volume resistivity, and electronic breakdown strength of ∼129 MPa, ∼42 %, ∼2.44 × 1012 Ω cm, and ∼78 kV mm−1 facilitate the excellent multifunctional property of the composite. Non-equilibrium molecular dynamics (NEMD) simulation further revealed that electron–phonon coupling mechanism in the “super-highway” thermally conductive pathways constructed by s-IL enhanced interfacial heat transfer. The customized interface structure design opens a new platform for the development of multifunctional thermal management materials with a low interfacial heat resistance in electronic devices filed.