Preparation, characterization and determination of magnetic properties of ferrofluids using chitosan-coated magnetic nanoparticles and tween 80 as surfactant for hyperthermia applicationAuthor(s): Thalia Camila Coelho, Mauro Cesar Marghetti Laranjeira, Rogerio Laus, Valfredo Tadeu de FÃÂ¡vere, Cristiano da Silva Teixeira, Mauricio Rigoni, Nelson Jhoe Batistela
Magnetite and maghemite nanoparticles were prepared by co-precipitation and oxidation methods, respectively. The magnetic nanoparticles obtained were coated with a layer of the surfactant Tween 80 dispersed in chitosan (CTS) solution. The infrared spectroscopy (IR) analysis confirmed the presence of all functional groups of iron oxides and the thermogravimetric analysis revealed a structural difference between the magnetic nanoparticles. Xray diffraction (XRD) results of the naked oxides and ferrofluids revealed that the resultant nanoparticles were naked oxides with a spinel structure. Magnetic measurement revealed that the saturated magnetization of the uncoated nanoparticles was higher than that of the coated nanoparticles. All samples were placed within an alternating magnetic field and it was observed that the maximum temperatures obtained for the magnetite, maghemite, magnetite/CTS and maghemite/CTS were 48.3, 49.9, 42.5 and 43.3ï°C, respectively. Therefore, magnetic nanoparticles do, indeed, appear to be promising as a potential magnetic support for hyperthermic applications.