Synthesis of a soluble polyaniline–ferrite composite: magnetic and electric properties

We report the preparation of a processible magnetite/polyaniline (Fe₃O₄/PANI) nanocomposite, containing dodecylbencensulfonic acid (DBSA) as a surfactant and dopant, with both magnetic and conducting properties. Different amounts of Fe₃O₄ nanoparticles were successfully disposed with FeCl₃ solution to prevent their aggregation in the solution by the application of common ion effect. The magnetic properties of the resulting composites were investigated by a quantum design magnetometer (PMPS). The (Fe₃O₄/PANI) nanocomposite showed at 300 K no loop of hysteresis indicating the superparamagnetic nature. The saturation magnetization varies from 0.167 to 28.45 emu/g with increasing Fe₃O₄ content. Zero field cooling (ZFC) and Field cooling (FC) profiles showed that the polyaniline matrix allows each ferrite nanoparticles to behave independently and interparticle interactions are not important for iron oxide content lower than 36 wt.%. The electrical conductivity of composites was found to be higher than that of the pure PANI in spite of the insertion of the insulating material Fe₃O₄ particles. It is noticeable that conductivity increases with low Fe₃O₄ particles content and then decreases. Structural characterization by X-ray diffraction (XRD), UV spectroscopy and thermogravimetric analysis (TGA) have been performed.