Evaluating the performance of citric acid as stabilizer and doping agent in an environment friendly approach to prepare electromagnetic nanocomposite particles

The objective of this investigation is to find a less‐expensive and less‐toxic environmentally benign route for the preparation of magnetic PANI nanocomposite particles. For this citric acid, a weak organic tricarboxylic acid has been used during seeded chemical oxidative polymerization of aniline in presence of variable amounts of Fe₃O₄ nanoparticles. Nanosized Fe₃O₄ particles are first prepared by co‐precipitation of Fe²⁺ and Fe³⁺ from their alkaline solutions. Then in the second step, magnetic nanocomposite particles—named as Fe₃O₄/PANI—are prepared by seeded chemical oxidative polymerization of aniline using ammonium persulfate (APS) as oxidant. Independent of Fe₃O₄ content, Fe₃O₄/PANI nanocomposite particles possessed comparable high electrical conductivity having the same magnitude as HCl‐doped PANI particles (2.13 × 10⁻³ S/cm). This result suggested that addition of citric acid during seeded chemical oxidative polymerization not only promoted solubilization of aniline but also functioned as stabilizer and doping agent. Iron oxide content critically influenced the stability, morphology, and magnetic properties of the produced nanocomposite particles. The saturation magnetization and magnetic susceptibility increased with the increase of Fe₃O₄ content. The nanocomposite particles prepared with core/shell ratio of 0.6/1 (w/w) exhibited the strongest paramagnetism and aligned into fiber‐like structure. The analysis of electromagnetic properties and spectral data from FTIR, X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), and thermogravimetry (TG) confirmed the complete coverage of Fe₃O₄ nanoparticles by PANI layer. POLYM. COMPOS., 39:4628–4636, 2018. © 2017 Society of Plastics Engineers