Synthesis and Characterization of Superparamagnetic Fe₃O₄@PDA Core-Shell Structure Nanoparticles

Superparamagnetic Fe₃O₄@PDA core-shell structure nanoparticles were synthesized via polyol thermo decomposition and solution oxidation.The structure,morphology and component were characterized by X-Ray Diffraction (XRD),Transmission Electron Microscopy (TEM),Fourier Transform Infrared Spectroscopy (FT-IR),and Thermogravimetric Analysis (TG),etc.The magnetic properties of the samples were measured using physical properties measurement system (PPMS).Results showed that the size of Fe₃O₄@PDA could be controlled by adjusting the molar ratio of ammonia to DA and reaction time.When the mass fraction of Fe₃O₄ in Fe₃O₄@PDA was about 5%,Fe₃O₄@PDA was superparamagnetic and the saturation magnetization was 3.8 emu/g,which was 36% higher than the theoretical value.