The use of a laponite dispersion to increase the hydrophilicity of cobalt-ferrite magnetic nanoparticles

Abstract In the literature, several attempts have been made to synthesize and later to modify magnetic nanoparticles to make them feasible for several applications. For biomedical applications, magnetic nanoparticles and clay minerals were combined to form a material that is both stable and biocompatible. In this context, composites with ratios of 4.70, 2.35 and 1.17 (weight/weight) of Cobalt Ferrite and Laponite were synthesized and characterized. These composites were treated with acid, and consequently the laponite was converted into an amorphous silica matrix around the magnetic nanoparticles. This morphology was confirmed using Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD). The particle size distribution, obtained by Transmission Electron Microscopy (TEM), was used as an input parameter for the polydispersity function in the Small Angle X-ray Scattering (SAXS) analysis. The latter was also applied to verify the particle shapes and aggregates for each composite. It was demonstrated by Thermal Gravimetric Analysis (TGA), that these materials, except for the composite with the highest ratio, adsorbed at least one order of magnitude more water than pure Cobalt Ferrite nanoparticles. Thus, increasing the hydrophilicity properties of the Cobalt Ferrite - laponite/silica system. A preliminary magnetization experiment corroborated with these findings and showed that a fraction of the system is not in the superparamagnetic regime at room temperature.