SYNTHESIS AND FERROMAGNETIC PROPERTIES OF COMPOSITES OF A WATER-SOLUBLE POLYANILINE COPOLYMER CONTAINING IRON-OXIDE

Composites of water-soluble conducting polyaniline copolymers, poly(an iline-co-aminobenzenesulfonic acid) (PAOABSA), containing gamma-Fe(2)O (3)magnetic particles with nanometer size, were synthesized by a chemi cal method. The ferromagnetic properties of the resulting PAOABSA comp osites were measured as a function of the pH value of the reaction sol ution, the sulfonated degree of the copolymer, and the concentration o f FeCl2. The structure of the composites was characterized by means of elemental analysis, FTIR, XPS, and X-ray diffraction. It was found th at increasing the pH value of the reaction solution and the concentrat ion of FeCl2 is favorable for an enhancement of the saturated magnetiz ation. As high as 33.2 emu/g of saturated magnetization for the PAOABS A composites was observed. No hysteresis loop (i.e. H-c = 0) was obser ved, which is independent of the preparation conditions. Structure cha racterizations show that iron oxide existing in the composite is mainl y gamma-Fe2O3, which is responsible for the ferromagnetic properties o f the PAOABSA composites, whereas gamma-Fe2O3 magnetic particles nanom eter in size (similar to 85 nm) may be attributed to a lower coercive force (i.e. H-c = 0) of the composites. (C) 1998 John Wiley & Sons, In c.