Fe₃O₄ Nanoparticle-Decorated Graphene Oxide Nanosheets for Magnetic Assembly of Artificial Nacre

Natural nacre, often referred as nature’s armor, has a typical “brick-and-mortar” hierarchical micro-/nanoscale multilayer microstructure and remarkable tensile strength and toughness. The highly ordered multilayer microstructure of nacre provides valuable insights into constructing advanced nanocomposites. Although significant success has been achieved in simulating artificial nacre-mimetic materials on a laboratory scale, it is still difficult to apply on a large scale because of time-consuming sequential depositions. In this study, a rapid and large-scalable magnetic assembly process for the fabrication of the graphene oxide (GO)-based composite film that mimics the structure of nacre was reported. Magnetic GO nanosheets were synthesized by decorating Fe3O4 nanoparticles on the surface of GO nanosheets and then assembled with poly(vinyl alcohol) (PVA) solution to form nacre-mimetic nanocomposites via the magnetic assembly technique. The tensile strength and toughness of the MGO–PVA film can reach 248.0 ± 6.7 MPa and 7.0 ± 0.5 MJ·m–3, which are 5.0 and 4.0 times higher than the pure MGO film, respectively. More interestingly, after in situ reduction by hydroiodic acid, the tensile strength reached as high as 340.0 ± 6.2 MPa. This work offers a rapid process of fabricating strong integration nacre-inspired materials, which shows applications in engineering, aerospace, flexible energy devices, and electromagnetic interference shielding materials.