Synthesis and surface coating/functionalization of iron oxide nanoparticles and study of their properties

Abstract

Magnetic iron oxide nanoparticles have drawn tremendous attraction from both fundamental aspect as well as applications in biomedicine such as magnetic bio-separation, detection of biological entities, magnetic resonance imaging, magnetic fluid hyperthermia and targeted drug delivery due to their fascinating magnetic properties. These properties of iron oxide nanoparticles can be tuned by modifying their phase, size, shape and surface coating of the nanoparticles. In the present thesis, synthesis of iron oxide nanoparticles with different morphology and their surface coating/functionalization were carried out. The structural, morphological, vibrational, magnetic and optical properties of these synthesized products were characterized by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), microRaman spectroscopy, Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), ultraviolet-visible spectroscopy (UV-Vis) and photoluminescence spectroscopy (PL). In the first part of the thesis deals with synthesis and characterization of iron oxide (hematite and magnetite) nanoparticles with different morphology. Hematite nanorods were synthesized by reverse micelles method using cetyltrimethyl ammonium bromide (CTAB) as a surfactant and calcined at 300 °C. Nanorods have hexagonal crystal structure with diameter of 30-50 nm and length 120-150 nm. A weak ferromagnetic behavior was observed with saturation magnetization (Ms) of 0.6 emu g-1 and coercive force (Hc) of 25 Oe. Ferromagnetic and#945;-Fe2O3 nanoparticles were synthesized by gel evaporation method in air at 300 and#8304;C. The average size of the as synthesized and#945;-Fe2O3 nanoparticle was estimated to be 30 nm and the particles were of good crystalline nature. The ferromagnetic properties of the nanoparticles are due to the existence of and#947;-Fe2O3 phase along with and#945;-Fe2O3.