Synthesis, characterisation, and evaluation of core-shell Fe3O4/SiO2/polypyrrole composite nanoparticles

This work reported a facile synthetic approach to synthesise core-shell Fe3O4/SiO2/polypyrrole composite nanoparticles with the superparamagnetic Fe3O4 nanoparticles as the inner core. The core-shell Fe3O4/SiO2/polypyrrole composite nanoparticles were prepared through a three-step approach involving co-precipitation for the synthesis of Fe3O4 nanoparticles, Stober method for SiO2 intermediate layer coating and solvothermal methods for polypyrrole shell. The as-prepared nanoparticles were characterised using transmission electron microscope, X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analyses and vibration sample magnetometer. The particle size of the inner core Fe3O4 nanoparticles was found to be 15 +/- 3 nm, and the thicknesses of the SiO2 shell and polypyrrole shell were approximate to 2.5 and approximate to 5 nm, respectively. From Fe3O4 nanoparticles to Fe3O4/SiO2 and then to Fe3O4/SiO2/polypyrrole composite nanoparticles, the magnetic saturation gradually decreases from 67 to 34 emu/g, then dropped to 7 emu/g. The as-prepared Fe3O4/SiO2/polypyrrole composite nanoparticles showed potential applications in drug and gene delivery systems.