Multifunctional melamine-based multilayer foam with heterogeneous alternating structure towards electromagnetic interference shielding

With the rapid development of 5 G technology, there is an urgent need to endow electromagnetic interference (EMI) shielding materials multifunctionality to cope with various harsh environments. Herin, a multifunctional melamine-based EMI shielding composite with heterogeneous alternating multilayer structure were fabricated through the layer-by-layer stacking method, consisting of Ni coated melamine foam ([email protected]) layers, Fe3O4@polydimethylsiloxane dipped MF layers (Fe3O4@PDMS/MF) and metallized polyimide fabric layer ([email protected]). The synergistic electromagnetic loss and interfacial polarization loss formed by the selectively distributed conductive Ni coating and magnetic Fe3O4 nanoparticles result in a high EMI shielding effectiveness (SE) of 54.20 dB with an absorption (A) value of 0.51 for the multilayer MF-based composite. Moreover, since the micro/nano porous structure, the nonflammability of MF, the functional Ni coating and Fe3O4@PDMS filling, the multilayer foam owns thermal insulation and flame retardancy. This work provides a viable strategy for designing absorption-based EMI shielding materials with thermal insulation and flame retardancy, which accords with the next generation of multifunctional EMI shielding materials.