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Polyaniline (PANI) nanocomposites reinforced with tungsten oxide (WO3) nanoparticles (NPs) and nanorods (NRs) are fabricated via a facile surface-initiated-polymerization (SIP) method. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) characterizations reveal the uniform coating of polymer on the filler surface and a good dispersion of the nanofillers within the polymer matrix. Unique negative permittivity is observed in pure PANI and its nanocomposites. The switching frequency (frequency where real permittivity switches from negative to positive) can be easily tuned by changing the particle loading and filler morphology. Conductivity measurements are performed from 50∼290 K, and results show that the electron transportation in the nanocomposites follows a quasi 3-d variable range hopping (VRH) conduction mechanism. The extent of charge carrier delocalization calculated from VRH well explains the dielectric response of the metacomposites. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) reveal an enhanced thermal stability of the nanocomposites with the addition of nanofillers as compared to that of pure PANI.

Arrays of nanowires and nanotubes of antimony-telluride (Sb2Te3) have been fabricated by an electrodeposition technique. Scanning electron microscopy was employed to characterize the morphology and size of the fabricated Sb2Te3 nanowires and nanotubes. Wavelength dispersive spectroscopy analysis confirmed the composition of the fabricated nanowires and nanotubes. The composition of the nanowires fabricated at a cathodic current density of 10 mA cm−2 and nanotubes fabricated at a cathodic current density of 5.5 mA cm−2 was found to be ∼39% Sb and ∼61% Te (2 : 3 ratio between Sb and Te). The fabricated Sb2Te3 nanowire and nanotube arrays were found to be polycrystalline with no preferred orientation. The average lamellar thickness of the nanowires and nanotube crystallites was determined using the Scherrer equation and found to be ∼36 nm and ∼43 nm, respectively. The measured room temperature Seebeck coefficients for the Sb2Te3 nanowires and nanotubes were +359 µV K−1 and +332 µV K−1, respectively, confirming that the Sb2Te3 nanowires and nanotubes were p-type. The electrical resistance measurements indicated that the resistance of the Sb2Te3 nanowires and nanotubes decreased with increasing temperature, consistent with semiconducting behavior.