Conducting and magnetic hybrid polyaniline/nickel composites

Abstract

Hybrid organic/inorganic polyaniline/nickel composites were prepared by the in-situ oxidation of aniline hydrochloride with ammonium peroxydisulfate in the presence of various portions of nickel microparticles. Electron microscopies demonstrated the coating of nickel with polyaniline. FTIR and Raman spectroscopies indicated the reduced degree of polyaniline protonation. As a consequence, the composites containing 7.2–58.8 wt% of nickel had the conductivity of the order of 10−3–10−2 S cm−1, i.e. several order of magnitude lower than the conductivity of polyaniline or nickel. The conductivity as a function of applied pressure is also reported. Relatively low conductivity of composites is explained by the partial reduction of polyaniline with hydrogen gas evolved during the synthesis and consequent hydrogenation of polyaniline catalysed by nickel. The accompanying partial dissolution of nickel manifests itself by the reduced composite yield. The reason why hydrogen is generated mainly after the synthesis of polyaniline is discussed. The magnetic properties afforded by nickel are also reported. The composites dispersed in thermoplastic polyurethane matrix providing mechanical properties have been tested for electromagnetic interference shielding.