SYNTHESIS OF SURFACE-MODIFIED SUPERPARAMAGNETIC IRON OXIDE-NANOCOMPOSITES

Abstract

The present report describes the synthesis of surface-modified superparamagnetic iron oxide nanocomposites. Wet chemical method has been employed for their synthesis. These particles have been characterized by employing advanced analytical tools like XRD, FESEM, TEM, FT-lR, UV-Visible and XPS. VSM has been used for analysing their magnetic behavior. The bare y-Fe203 was spherical particles with an average particle size of 13 nm having cubic structure. These particles demonstrated superparamagnetic behavior at room temperature with a magnetic saturation value (Ms) of 72 emu/g. The optical spectra displayed three peaks on a broad band (480 nm, 380 mn and 254 nm) lying between 200-600 nm. The doping of Ag in to y-Fe2O3 phase produced bigger clusters of particles with porosity, in which Ag nanoparticles gets encapsulated into the pores of y-Fe203. The onset of absorption in this case has shifted to higher energy indicating the nanocluster to consist of smaller nanoparticles. The y-Fe203 cluster has an average size of 45 nm and the encapsulated Ag nanoparticles had an average size of 6.5 nm. These nanocomposites were superparamagnetic similar to bare y-Fe203, but the magnetization saturation value due to these nanoclusters increased significantly to more than twofold. In the presence of PVA, y-Fe2O3 nanoparticles of relatively smaller size are produced and depicted a reduction in their size with increasing PVA. For 0.01% PVA, the average size of these particles was observed to be 6.5 nm. These particles also display superparamagnetic behavior, but with a slight decrease in value of saturation magnetization compared to the bare y-Fe203 nanosystem. These particles are suggested to find application for drug delivery and magnetic resonance imaging and as ferrofluids