Shielding Effectiveness Study of Barium Hexaferrite-Incorporated, β-Phase-Improved Poly(vinylidene fluoride) Composite Film: A Metamaterial Useful for the Reduction of Electromagnetic Pollution.

The present work reports the high electromagnetic interference (EMI) shielding effectiveness of ∼-93.5 dB at 8.63 GHz and -97.6 dB at 8.61 GHz in the X- and Ku-bands for 10 and 20 wt % of barium hexaferrite (BaH) nanoparticle-loaded poly(vinylidene fluoride) (PVDF)-based composite films with a thickness of ∼0.210 and 0.260 mm, respectively. BaH-PVDF composite films with a layer structure have been considered in the present report in order to establish an excellent EMI shielding material for the suppression of electromagnetic pollution, with good control on flexibility, surface area, and thickness. Structural and morphological measurements reveal that the polar β-phase crystallization of the BaH-PVDF composite films has been enhanced in comparison to the pure PVDF film, and these measurements also reveal the influence of BaH nanoparticles on structural alteration from nonpolar α-phase to the polar/electroactive β-phase of the PVDF matrix. The resultant BaH-PVDF composite films produce multiple interfaces between magnetic BaH nanoparticles and β-phase-enriched electroactive PVDF, which plays the most significant role for the enhancement of the EMI shielding effectiveness (SE) in the microwave/GHz frequency range. This high value of the EMI SE with >99.999999999% attenuation has not been found so far in the PVDF-based composite materials by anyone else. This particular feature of BaH-PVDF composite materials suggests that the BaH-PVDF composite films can be considered as the most useful ones for the fabrication of lightweight, flexible, and thickness-controlled EMI shielding materials for the reduction of pollution created by the electromagnetic waves in the microwave/GHz frequency region.