Electronic, structural, and magnetic properties of cobalt aggregates embedded in polypyrrole

In this paper, we report on the synthesis and characterization of cobalt aggregates electrochemically incorporated on composite polypyrrole films. XAS (X-ray absorption spectroscopy) was used to probe the atomic local order in these composites and to furnish new insights into the metal/polymer interaction. A complete understanding of the incorporation process and its evolution was achieved by in situ XAS measurements at different stages of the electrochemical process. These results indicate that the reaction starts with the Co2+ entrapped in the polymeric matrix as a complex [-[(C4H2N)3CH3(CH2)11OSO3-]6Co2+]. The reduction of this complex leads to the synthesis of Co aggregates in the film. Measurements at the O and N K edges evidence that the main interaction between Co aggregates and the polymer is verified via Co−N bonds, the N originating from the polypyrrole (PPy) amine group. The pH effect on the metal/polymer interaction is discussed. Scanning electron microscopy (SEM) measurements show the formati...