Composite of polyaniline containing iron oxides with nanometer size

A composite of polyaniline (PANI) containing iron oxides with nanometer size was synthesized by a chemical method. The structure, electrical and magnetic properties of the resulting PANI-FexOy composites depend on the pH value of the reaction medium and temperature. For the basic preparation conditions (e.g. pH 14), the resulting PANI-FexOy composite can be attracted by a magnet at room temperature, and its magnetization with the applied magnetic field exhibits a hysteresis loop with H-c=0. It has been demonstrated that nanocrystalline ferromagnetic particles of Fe3O4 with 14.0 nm size correspond to super-paramagnetic properties observed from PANI-FexOy composites. For the acidic conditions (e.g. pH 1), on the other hand, the electrical properties of the resulting PANI-FexOy composite show a semiconducting behavior. By comparison with PANI-Cl-, the lower conductivity (about 10(-4) S/cm) for PANI-FexOy composite may be due to the presence of iron oxides in the composite, although its doping degree is the same as that of PANI-Cl-.