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 −1 K −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.