Study of Magnetic and Electrical Properties of Poly(o-phenylenediamine)/Manganese Substituted ZnFe2O4 Nanocomposites

Journal of Inorganic and Organometallic Polymers and Materials - Different concentrations of ZnFe2O4 and manganese substituted ZnFe2O4 nanoparticles (10%, 20% and 30%) dispersed...     

Synthesis,characterization, thermal,electrical and electrochemical studies of oligo nitrobenzimidazoles and their p–n diode applications

Three novel nitro oligobenzimidazoles, oligo-2-(6-nitro-1H-benzo[d]imidazol-2-yl)phenol (OBINP2), oligo-3-(6-nitro-1H-benzo[d]imidazol-2-yl)phenol (OBINP3) and oligo-4-(6-nitro-1H-benzo[d]imidazol-2-yl)phenol (OBINP4) were synthesized by oxidative polycondensation of benzimidazole monomers with NaOCl in aqueous alkaline medium. The structure of the monomers and oligomers were confirmed by FT-IR, UV–Vis, ¹H and ¹³C NMR spectroscopic techniques. The monomer BINP2 and its oligomer are showing dual emission through excited state intramolecular proton transfer process. The band gap values of monomers and oligomers were calculated from both UV–Vis spectroscopic and cyclic voltammetric data. Theoretical band gap values of monomers obtained from DFT were compared with experimentally calculated band gap values. The electrical conductivity of I₂ doped and undoped oligomers were measured using two point probe technique and are showing good correlation with the charge densities on imidazole nitrogen obtained from Huckel method. The conductivity of oligomers increases with increase in iodine vapour contact time up to 144 h. The variation of dielectric properties of oligomers has been investigated at different frequency and temperature. Among the oligomers, OBINP3 is having greater thermal stability as evidenced by its high carbine residue of around 65% at 600 °C in thermogravimetric analysis.     

Electrical and magnetic properties of poly(<Emphasis Type="Italic">m</Emphasis>-phenylenediamine)/NiFe<Subscript>2</Subscript>O<Subscript>4</Subscript> nanocomposites

Poly(m-phenylenediamine) (PmPD)/NiFe₂O₄ nanocomposites were synthesized by in situ oxidative polymerization containing two different ratios of NiFe₂O₄ nanoparticles (10 and 20%). Dielectric studies of PmPD/NiFe₂O₄ nanocomposites were carried out at different temperature and frequency. Dielectric constants of PmPD/NiFe₂O₄ nanocomposites vary with the concentration of NiFe₂O₄ nanoparticles. Magnetic measurements of NiFe₂O₄ nanoparticles and PmPD/NiFe₂O₄ nanocomposites showed that they have ferromagnetic behaviour at room temperature. The XRD patterns of PmPD/NiFe₂O₄ nanocomposites are confirming the incorporation of NiFe₂O₄ nanoparticles into PmPD polymer. Room temperature Mössbauer spectrum of NiFe₂O₄ nanoparticles demonstrated that the Fe is in 3+ oxidation state with cubic structure. The SEM image of PmPD shows sphere like morphology. TGA suggest that thermal stability of PmPD/NiFe₂O₄ nanocomposites is greater than PmPD.