Vertical Graphene Nanosheet/Polyimide Composite Films\nfor Electromagnetic Interference Shielding

Abstract

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