Electromagnetic wave absorption properties of polymer-derived magnetic carbon-rich SiCN-based composite ceramics

Lightweight poly(vinylidene fluoride) based quaternary nanocomposite foams with efficient and tailorable electromagnetic interference shielding properties

“…In contrast with pure PVDF, μ ″ and tan δ μ of various PVDF nanocomposites were significantly improved (Figure 6E,F), and tan δ μ of PVDF nanocomposites could severally attain to 0.32, 0.32, 0.23, 0.19 (Figure 6F), illustrating the enhancement of the magnetic energy loss capability of PVDF specimens. [ 70 ] Comparing Figure 7C,F, it should be found that the tan δ ε of PVDF nanocomposites was higher than tan δ μ , suggesting that dielectric loss was the main type of electromagnetic loss. From the analysis of Figure 6, the addition of Ni formed a great deal of heterogeneous interfaces in PVDF matrix, and the interface polarization loss and natural resonance of PVDF specimens were enhanced, which promoted the dielectric loss and magnetic loss performance of PVDF specimens.…”

“…Apparently, the tan δ ε of PVDF specimens also improved significantly compared to pure PVDF, revealing that the addition of nanofillers has effectively improved the dielectric loss property of PVDF specimens. [ 70 ] Since the PVDF was non‐magnetic material, μ ' of pure PVDF was stable around 1 in Figure 6D. After nanofillers were added to PVDF matrix, μ ' of PVDF specimens fell slightly (all down to 0.8).…”

“…As widely known, EMI shielding performances of polymers depend on their complex permittivity and complex permeability, where the real parts ( ε ' and μ ') and imaginary parts ( ε ″ and μ ″) show the storage capacity and dissipation capacity of EM energy, separately. [ 70 ] Thus, to clearly account for the enhancement mechanism of EMI shielding performance, the dielectric parameters of various PVDF specimens in 8.2–12.4 GHz were plotted in Figure 6.…”

“…The dielectric loss tangent (tan δ ε ) described the damping capacity of nanocomposites to electric energy. [ 70 ] Figure 6C revealed the variation of the tan δ ε value of various PVDF specimens in X‐band. Apparently, the tan δ ε of PVDF specimens also improved significantly compared to pure PVDF, revealing that the addition of nanofillers has effectively improved the dielectric loss property of PVDF specimens.…”

“…From the analysis of Figure 6, the addition of Ni formed a great deal of heterogeneous interfaces in PVDF matrix, and the interface polarization loss and natural resonance of PVDF specimens were enhanced, which promoted the dielectric loss and magnetic loss performance of PVDF specimens. [ 70 ] These laid the foundation for the reinforcement of EMI shielding performances of PVDF specimens.…”