Multifunctional composite with porous gradient structure for absorption-oriented ultrahigh electromagnetic interference shielding

The stable porous composite encapsulated with polydimethylsiloxane (PDMS) consisting of Ni-plated melamine foam in different densities and Fe3O4-polyaniline (Pani) layer, exhibiting a positive conductive gradient to attain an effective shielding and absorbing effect on the electromagnetic wave (EMW). As the difference in conductivity of each layer and the presence of porous interfaces bring additional interface polarization while achieving multiple reflections, dielectric and magnetic losses of EMW, the electromagnetic interference shielding effectiveness (EMI SE) of the composite achieves 90.4 dB with an absorption value of 0.68. Furthermore, owing to the encapsulation effect of PDMS and the construction of Fe3O4-Pani layer, additional photothermal conversion and hydrophobicity properties are conferred while satisfying the mechanical and chemical stability of the composite. It provides a unique approach to the multi-functional integration of composites and opens up design ideas for sophisticated shielding composites in the future communication field.