Metal-coordination-driven self-assembly synthesis of porous iron/carbon composite for high-efficiency electromagnetic wave absorption

Abstract

Hydrophilic-hydrophobic microphase separation is an important mechanism to promote aqueous polymer self-assembly. However, it is rarely used in the construction of magneto-dielectric absorbers in the interdisciplinary research involving organic polymer and inorganic hybrid material. Herein, a novel metal-coordination-driven self-assembly strategy is proposed for fabricating organic–inorganic composite co-assemblies by combining resorcinol–formaldehyde resin as carbon precursor and iron-containing polymer self-assemblies as soft template. Co-assemblies are then transformed into porous iron/carbon (Fe/C) composites with spherical Fe nanoparticles and micro-mesopores that form in graphited carbon matrix through high-temperature pyrolysis. The minimum reflection loss of Fe/C-800 composite in paraffin matrix with 10% filler loading can reach −57.8 dB, while the effective absorption bandwidth of 5.3 GHz can cover the whole X band. It is considered that the co-assemblies-derived microstructure and magneto-dielectric composition contribute to the multiple reflection, polarization loss, conductive loss, ferromagnetic resonance and eddy current loss for high-efficiency electromagnetic wave absorption. In general, this work opens up new prospects for designing and preparing high-performance magneto-dielectric absorbers via a novel metal-coordination-driven self-assembly strategy.