Carbon foams derived from emulsion-templated porous polymeric composites for electromagnetic interference shielding

A series of carbon foams (CFs) were fabricated from the emulsion-templated porous polymeric composites, following with hypercrosslinking and carbonization. The polymeric composites were constituted by syndiotactic polystyrene (sPS), carbon nanotubes (CNTs) and magnetic Ni@CNTs. The addition of nanofillers was beneficial to the carbonization, resulting in less shrinkage, higher graphitization degree, lager emulsion-templated voids and nanofibrous pore walls. The composite CFs showed higher robustness (up to 19.7 MPa cm³ g⁻¹), more hydrophobic surface (water contact angle up to 148°) and larger specific surface area (up to 144 m² g⁻¹). In particular, the electrical conductivity (up to 97 S m⁻¹) and electromagnetic interference (EMI) shielding effectiveness (EI) (up to 78.0 dB) were greatly enhanced when the CNTs and Ni@CNTs were simultaneously employed. The conduction losses caused by conductive network of residual carbon network of carbonized sPS and the nanofillers, polarization losses from interfacial polarization between carbonized sPS and nanofillers, dielectric loss within mesopores and magnetic loss from Ni@CNTs contributed to the enhanced shielding effectiveness. The carbon foams can be prefect succedanea of the commercial EMI shielding materials in the aerospace and wireless telecommunication fields.