Synthesis and characterization of polyvinylimidazole-grafted superparamagnetic iron oxide nanoparticles (Si-PVIm-grafted SPION)

Polyvinylimidazole (PVIm)-grafted superparamagnetic iron oxide nanoparticles (SPION) (Si-PVIm-grafted Fe3O4 NPs) were prepared by grafting of telomere of PVIm on the SPION. The product identified as magnetite, which has an average crystallite size of 9 +/- 2 nm as estimated from X-ray line profile fitting. Particle size was estimated as 10.0 +/- 0.5 nm from TEM micrographs. Mean particle size is found as 8.4 +/- 1.0 nm which agrees well with the values calculated from XRD patterns (9 +/- 2 nm). Vibrating Sample Magnetometer (VSM) analysis explained the superparamagnetic nature of the nanocomposite. Thermogravimetric analysis showed that the Si-Imi is 25 % of the Si-PVIm-grafted SPION, which means an inorganic content is about 75 %. Detailed electrical and dielectric properties of the properties of the product are also presented. The conductivity of the sample increases significantly with temperature and has the value in the range of 1.14 x 10(-7)-1.78 x 10(-4) S cm(-1). Analysis of the real and imaginary parts of the permittivities indicated temperature and frequency dependency representing interfacial polarization and temperature-assisted reorganization effects.