COMPOSITE OF POLYANILINE CONTAINING IRON-OXIDES WITH NANOMETER-SIZE

A composite of polyaniline (PANI) containing iron oxides with nanomete r 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 composi te can be attracted by a magnet at room temperature, and its magnetiza tion with the applied magnetic field exhibits a hysteresis loop with H -c=0. It has been demonstrated that nanocrystalline ferromagnetic part icles of Fe3O4 with 14.0 nm size correspond to super-paramagnetic prop erties observed from PANI-FexOy composites. For the acidic conditions (e.g. pH 1), on the other hand, the electrical properties of the resul ting PANI-FexOy composite show a semiconducting behavior. By compariso n with PANI-Cl-, the lower conductivity (about 10(-4) S/cm) for PANI-F exOy composite may be due to the presence of iron oxides in the compos ite, although its doping degree is the same as that of PANI-Cl-.