Synthesis, characterisation, and evaluation of core–shell Fe ₃ O ₄ /SiO ₂ /polypyrrole composite nanoparticles

Abstract

This work reported a facile synthetic approach to synthesise core–shell Fe 3 O 4 /SiO 2 /polypyrrole composite nanoparticles with the superparamagnetic Fe 3 O 4 nanoparticles as the inner core. The core–shell Fe 3 O 4 /SiO 2 /polypyrrole composite nanoparticles were prepared through a three‐step approach involving co‐precipitation for the synthesis of Fe 3 O 4 nanoparticles, Stöber method for SiO 2 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 Fe 3 O 4 nanoparticles was found to be 15 ± 3 nm, and the thicknesses of the SiO 2 shell and polypyrrole shell were ∼2.5 and ∼5 nm, respectively. From Fe 3 O 4 nanoparticles to Fe 3 O 4 /SiO 2 and then to Fe 3 O 4 /SiO 2 /polypyrrole composite nanoparticles, the magnetic saturation gradually decreases from 67 to 34 emu/g, then dropped to 7 emu/g. The as‐prepared Fe 3 O 4 /SiO 2 /polypyrrole composite nanoparticles showed potential applications in drug and gene delivery systems.