SYNTHESIS AND ELECTRICAL-MAGNETIC PROPERTIES OF POLYANILINE COMPOSITES

Composites of polyaniline (PANI) with both conducting and ferromagneti c feature were synthesized by an improved method proposed by the autho rs. The electrical and ferromagnetic properties of the composites were measured as a function of the concentration of KOH solution used duri ng polymerization. The conductivity of the composites at room temperat ure decreases with the increase of the concentration of KOH; the maxim um conductivity of 8.0 x 10(-1) S/cm can be obtained when 25 wt % of c oncentration of KOH was used. For a high concentration of KOH, ferroma gnetic properties of the composites including a high saturated magneti zation (similar to 10.0 emu/g) depending on the concentration of KOH s olution and a lower coercive force (H-c approximate to 0) independent of the concentration of KOH solution were observed. It has been demons trated that magnetic particles (Fe3O4) with nanometer size in the comp osites can be attributed to the ferromagnetic properties of the compos ites observed. For a lower concentration of KOH solution, on the other hand, the magnetic properties of the composites can be decomposed to Curie susceptibility chi(c) depending on the temperature and Pauli sus ceptibility chi(P) independent of the temperature. (C) 1998 John Wiley & Sons, Inc.