Heterogeneous silicon rubber composite foam with gradient porous structure for highly absorbed ultra-efficient electromagnetic interference shielding

Heterogeneous silicone rubber (VMQ)/silver plated glass fiber ([email protected])/multiwalled carbon nanotubes (MWCNT)/ferroferric oxide (Fe3O4) composite foams with gradient porous structure were fabricated through layer by layer combination and supercritical carbon dioxide (scCO2) foaming. The average electromagnetic interference shielding effectiveness (EMI SE) and absorption coefficient (A) of the composite foam are as high as 78.6 dB and 0.82 respectively, because of the reasonable progressive dissipation mechanism. The resonance cancellation caused by the encounter of incident and reflected electromagnetic (EM) waves further improved the microwave absorbing performance of the foam, and an absorption ratio of up to 94% can be obtained at 7.68 GHz. Moreover, the composite foam exhibits excellent stability of EMI shielding performance under multiple bending. This composite foam has great application prospects in the field of EM protection of wearable flexible electronics, high-power instruments and the forthcoming 5th-Generation communication products.