Synthesis, characterization, electrical transport and magnetic properties of PEDOT–DBSA–Fe3O4 conducting nanocomposite

Electrical transport and magnetic properties of newly synthesized conducting polymer nanocomposites involving poly(3,4-ethylenedioxythiophene) (PEDOT) and Fe3O4 nanoparticles are studied. Nanocomposite samples of varying proportions of inorganic to organic components were synthesized by adding EDOT monomer stabilized in miceller solution of DBSA (dodecylbenzene sulphonic acid) to aqueous colloidal dispersion of Fe3O4 nanoparticles, followed by oxidative polymerization using ammonium peroxodisulphate (APS). Transmission electron microscopic (TEM) photographs show presence of distinct spherical Fe3O4 naonparticles having diameter range of 20–40 nm and they are incorporated within the polymer chain in the nanocomposite samples. Temperature-dependent DC conductivity analysis indicates a smooth cross-over of the charge conduction from the high temperature 3D Mott's variable range hopping (VRH) mechanism to the 2D ES (Efros and Shklovoskii)-VRH behaviour at low temperature. Temperature-dependent DC magnetization studies reveal enhancement of blocking temperature (TB) in the nanocomposite samples compared to that of bare Fe3O4 nanoparticles. Core shell morphology of the nanoparticles seems to be the cause for lowering the value of saturation magnetization of the Fe3O4 nanoparticles. Estimated magnetic domain sizes are comparable to those of grain sizes for the nanocomposite samples having lower content of nanoparticles (P50 and P100). Temperature-dependent AC-susceptibility data also supports the superparamagnetic behaviour.