Self-assembly approach for the synthesis of electro-magnetic functionalized Fe3O4/polyaniline nanocomposites: Effect of dopant on the properties

Electro-magnetic functionalized Fe3O4/polyaniline (PANI) nanocomposites were synthesized by chemical oxidative polymerization in the presence of ammonium peroxydisulfate as an oxidizing agent. Polymerization was carried out independently using two different types of dopants, organic acids (camphorsulfonic acid (CSA) and p-toluenesulfonic acid (TSA)) and inorganic acid (hydrochloric acid). A plausible mechanism for the formation of the nanocomposites (NCs) is presented. During the formation of NCs, CSA/TSA also serves as a micellar template, whereas micelle formation is absent in the case of HCl. Fe3O4/PANI-CSA-NC, Fe3O4/PANI-TSA-NC and Fe3O4/PANI-HCl-NC were characterized for morphology, molecular structure, electrical conductivity and magnetic properties by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy (UV–vis) and superconductor quantum interference device (SQUID) measurements. The results indicate that dopant influence the properties of the NCs. TEM photographs of Fe3O4/PANI-CSA and Fe3O4/PANI-TSA reveal that the composite particles are spherical having a layer of PANI-CSA or PANI-TSA over Fe3O4 nanoparticles. Fe3O4/PANI-CSA-NC and Fe3O4/PANI-TSA-NC have better morphology, conductivity and high magnetic saturation (Ms) than that of Fe3O4/PANI-HCl-NC. Under applied magnetic field, the NCs exhibit the hysteresis loops of the ferromagnetic behavior. Ms value varies with content of Fe3O4 present in the composites.