Processible nanostructured materials with electrical conductivity and magnetic susceptibility: Preparation and properties of maghemite polyaniline nanocomposite films

We here present a versatile process for the preparation of maghemite/polyan iline (gamma-Fe2O3/ PAn) nanocomposite films with macroscopic processibilit y, electrical conductivity, and magnetic susceptibility. The gamma-Fe2O3 na noparticles are coated and the PAn chains are doped by anionic surfactants of omega-methoxypoly(ethylene glycol) phosphate (PEOPA), 4-dodecylbenzenesu lfonic acid (DBSA), and 10-camphorsulfonic acid (CSA). Both the coated gamm a-Fe2O3 and the doped PAn are soluble in common organic solvents, and casti ng of the homogeneous solutions gives free-standing nanocomposite films wit h gamma-Fe2O3 contents up to similar to 50 wt %. The morphology of the gamm a-Fe2O3 nanoparticles are characterized by transmission electron microscopy , UV-vis spectroscopy, and X-ray diffractometry. The gamma-Fe2O3/PAn films prepared from chloroform/m-cresol solutions of DBSA-coated gamma-Fe2O3 and CSA-doped PAn are conductive (sigma = 82-237 S/cm) and superpapamagnetic, e xhibiting no hysteresis at room temperature. The zero-field-cooled magnetiz ation experiment reveals that the nanocomposite containing 20.8 wt % gamma- Fe2O3 has a blocking temperature (T-b) in the temperature region of 63-83 K .