Hierarchical structured epoxy/reduced graphene oxide/Ni-chains microcellular composite foam for high-performance electromagnetic interference shielding

To simultaneously enhance the processability, electrical conductivity and mechanical properties of composite foam for high-performance electromagnetic interference (EMI) shielding application, in this work, the epoxy (EP)/reduced graphene oxide (rGO)/Ni-chains microcellular composite foam is prepared through strategy of combining the hierarchical structured aerogel skeleton and supercritical carbon dioxide (scCO2) foaming process. Benefiting from the construction of the rGO/Ni-chains bicontinuous conductive skeleton and introduction of microcellular structure, the EP/rGO/Ni-chains microcellular foam displays a "brick-and-mortar" structure and implements the multiple dissipation mechanism of electromagnetic (EM) wave to achieve outstanding EMI shielding efficiency (EMI SE) of 41.11 dB in X-band. Moreover, the selection of liquid epoxy as matrix avoids the use of large amounts of organic solvents, ensures the well processability of composite and realizes the excellent compressive strength (27.33 MPa) of the EP/rGO/Ni-chains microcellular foam with a density of 0.88 g/cm3, which shows great application value as a high-performance EMI shielding material.