Polypyrrole/lanthanum strontium manganite oxide nanocomposites: Elaboration and characterization

摘要

The synthesis of organic-inorganic hybrid polypyrrole (PPy)-lanthanum strontium manganite oxide La_(0.8)Sr_(0.2)MnO_3 (LSMO) nanocomposites via chemical oxidative polymerization of pyrrole in presence of LSMO nanoparticles using ferric chloride as oxidant and sodium p-toluene sulfonate as efficient dopant is investigated. The morphology of polypyrrole and its nanocomposites was examined by scanning electron microscopy which have shown that the presence of LSMO nanoparticles strongly affects the particle size of the nanocomposites. The specific interactions between the conducting polymer and the inorganic nanoparticles is highlighted by FTIR characterizations. Transmission electron microscopy and X-ray diffraction measurements of the nanocomposites confirm a core-shell structure with LSMO coated by polypyrrole macromolecular chains. Electrochemical properties of nanocomposites were investigated by cyclic voltammetry measurements in 2 M KOH. In such a media, polypyrrole nanocomposite electrode with 30 wt% LSMO nanoparticles has shown specific capacitance of 530 F g~(-1) which is significantly higher than pristine polypyrrole i.e., 246 F g~(-1). These charge storage differences between the pristine polypyrrole and polypyrrole/LSMO nanocomposite has been attributed to the morphology of the nanocomposite in which the particle sizes, the specific surface area, and pore size distribution have been modified with the incorporation of nanoparticles in the polypyrrole matrix.