Multilayered nacre-mimetic inspired flexible PEI film with high thermal conductivity and reliable dielectric performances

It is critically desired to integrate high in-plane thermal conductivity (TC) and distinguished electric insulation for thermal conductive film in modern electronic devices. Herein, integration of high TC and electric insulation in sandwich-like BNNSs@MWCNTs/PEI (S-BNNSs@MWCNTs/PEI) composite film has been successfully achieved by layer-by-layer spin coating and hot pressing inspired by highly ordered structure of natural nacre. The covalently bonded connections between BNNSs and MWCNTs are beneficial to create more efficient heat conduction path, which can partly decrease the interfacial thermal resistance and phonon scattering. The resultant S-BNNSs@MWCNTs/PEI composite films possess a high in-plane TC of 6.88 W m^?1K^?1. Meantime, benefiting from the alternating multilayer structure, the composite films exhibit satisfactory reliable dielectric performances with flexibility, which shows great potential in ceramics-filled polymer composite TIMs.