Bi-phase dispersible Fe₃O₄@Au core–shell multifunctional nanoparticles: synthesis, characterization and properties

Bi-phase dispersible (dispersible both in organic and aqueous medium) Fe3O4@Au core-shell multifunctional nanoparticles were synthesized by a modified nanoemulsion process. The formation of the core-shell multifunctional nanostructure was accomplished with the assistance of poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol)(PEO-PPO-PEO, MW = 5800) as the surfactant in two consecutive steps. The morphology and microstructure of core-shell multifunctional nanoparticles was revealed by transmission electron microscopy (TEM) and X-ray diffraction (XRD) patterns. The FTIR analysis proves the covering of the surfactant PEO-PPO-PEO on the surface of nanoparticles which enables an easy transfer of the prepared nanoparticles to organic and aqueous medium without additional surface decoration. The magnetic measurement performed by the using of vibration sampling magnetometry (VSM) manifests a soft ferromagnetic behavior at room temperature of the nanoparticles. The UV-Vis spectroscopic examination indicates the well-behaved surface plasmon owing to the nanostructured Au surface of Fe3O4@Au core-shell multifunctional nanoparticles. The nanoparticles can be directly dispersed in water phase and oil phase, and the processes of dispersion-collection of the nanoparticles were demonstrated for application readiness of such core-shell nanostructure.