Vertical Graphene Nanosheet/Polyimide Composite Films for Electromagnetic Interference Shielding

The development of carbon nanocomposite with high-performance electromagnetic interference (EMI) shielding has become vitally important for next-generation intelligent electronic devices. However, efficient EMI shielding for highly flexible and miniaturized devices is still a challenge. Here, a highly flexible and thin composite film composed of vertical graphene nanosheets (VGSs) and polyimide (PI) for EMI shielding is proposed. VGSs are prepared by activation-induced thermal chemical vapor deposition (CVD) for the first time, and the composite film is prepared by composing VGSs with PI via in situ polymerization. With the isotropic urchin-like nanostructure and agglomeration-free dispersion of VGSs, rich electrons conduction paths, enclosure nanostructure, and countless interfaces are constructed in PI matrix. The optimal composite film shows superior EMI shielding performance (an average EMI shielding effectiveness of 31.37 dB in the frequency range of 8.2-12.4 GHz can be detected with a thickness of 151 μm). Furthermore, the composite film also shows excellent thermal management performance. Suitable flexibility and robustness allow the composite film to bear even 2000 continuous bending cycles, and without appreciably decreasing its EMI shielding and thermal management performance, which establishes potentials for applications in EMI shielding and thermal management.