Fe ionic induced strong bioinspired Fe3O4@graphene aerogel with excellent electromagnetic shielding effectiveness

Abstract

The graphene oxides would be reduced by dopamine self-polymerization to self-assembly graphene hydrogel and the graphene building blocks were covered with polydopamine. In order to obtain stronger aerogel with excellent electromagnetic interference shielding effectiveness (EMISE), bioinspired by mussel byssus, Fe3+/Fe2+ were introduced into the preparation process. Fe ionic endowed the aerogel with a remarkable combination of high hardness and extensibility by hydroxyl/amine-Fe3+ chelation cross-links. When PH = 10, the Fe3O4 in-situ coated on the aerogel surface, which also enhanced the mechanical and magnetic loss properties of aerogel. After pyrolysis under 800 °C, Fe-N coordination complex and stable Fe3O4 still exhibited mechanical strengthening effect. As for EMISE, Fe/N doping and flower-like Fe3O4 were also beneficial for dielectric and magnetic polarity, thus improved its related properties. Compared with that of pristine graphene aerogel, the compressive strength of 4 mg/mL Fe3+ induced Fe3O4@graphene aerogel under 50% strain increased by 22.9% and high compressive recoverability under 90% strain was observed. The EMISE was also improved over wide band range of 2–18 GHz. For high frequency, SE value of samples with 2 mm thickness was as high as 41 dB. Furthermore, owing to annealing process, it could be inferred that it would be applied in high temperature filed.