Polyvinylimidazole (PVI)-grafted iron oxide nanoparticles (PVIgMNP) were prepared by grafting of telomere of PVI on the iron oxide nanoparticles. Crystalline phase was identified as magnetite with an average size of 9 nm estimated from X-ray line profile fitting. Particle size estimated from TEM by log-normal fitting was similar to 10 nm. FT-IR analysis showed that the binding of silane onto the surface of iron oxide is through unidentate linkage of Si-O. The AC characteristics of nanocomposites were analyzed via the capacitive impedance measurement method. And the effective conduction mechanism was found as correlated barrier hopping. dc activation energy of the product at around room temperature was found between 0.216 and 0.776 eV in good agreement with the earlier reports. It is found that the molar ratio of AA/PVI is effective on the DC conductivity and Activation energy of composites. The effects of grafting and alginic acid/polyvinylimidazole molar ratio on conduction mechanism were studied. (c) 2013 Elsevier Ltd. All rights reserved.