Adjustable Core-Sheath Architecture of Polyaniline-Decorated Hollow Carbon Nanofiber Nanocomposites with Negative Permittivity for Superb Electromagnetic Interference Shielding

In this work, the adjustable core-sheath architecture in the hollow carbon nanofibers/polyaniline (HCNFs/PANI) nanocomposites with negative permittivity and an outstanding electromagnetic interference (EMI) shielding performance have been developed. The effect of thickness for polyaniline sheath on the electrical property and EMI performance of HCNFs/PANI nanocomposites has been studied in detail. The results demonstrate that the highest electrical conductivity of 22.71 ± 0.10 S cm−1 and the largest EMI shielding effectiveness (SE) of 60–94 dB within the X-band range (8.0–12.4 GHz) is observed in the HCNFs/PANI nanocomposites with a HCNFs loading of 50 wt%. The excellent electrical conductivity, a changeable dielectric resonance from positive to negative in the X-band range, and the internal multiple scattering at interfaces between HCNFs and PANI are devoted to this unique EMI shielding performance in HCNFs/PANI nanocomposites. This work enables a new approach to create the novel structural polymeric materials with negative permittivity for EMI shielding. A novel hollow carbon nanofibers/polyaniline nanocomposite is constructed, which displays an outstanding electromagnetic interference shielding performance and unique negative permittivity in the X-band range.