Engineering closed-cell structure in lightweight and flexible carbon foam composite for high-efficient electromagnetic interference shielding

In this work, we develop a specifically engineered variant of carbonized melamine foam (cMF) by carrying systematic structural modifications with Au nanoparticles, graphene (G), Fe₃O₄ (IO) and poly(dimethyl siloxane) (PDMS). Our main goal is to construct a lightweight and flexible cMF composite with tailored 3D hierarchical architecture for achieving high-efficiency in electromagnetic interference (EMI) shielding. By capitalizing on the synergistic effect of the multifunctional components in the fabrication of the typical closed-cell structure, cMF-Au-G-IO/PDMS composite produced herein demonstrates superior physical properties including low density (116 mg/cm³), high conductivity (81.3 S/m), large specific surface area (708 m²/g), proven superparamagnetism (Ms = 22.6 emu/g), and moderate compressive strength (110 KPa), collectively leading to the significant attenuation effect towards EMI. The cumulative EMI shielding effectiveness (SE) of cMF-Au-G-IO/PDMS film with a thickness of 2 mm is determined as 30.5 dB in X band (8.2–12.4 GHz). Interestingly, SE is further raised up to 52.5 dB when the film thickness is increased to 10 mm. Hence, we envision the emergence of multifunctional cMF-based composite as a promising engineering system for fulfilling the demanding applications in EMI shielding.