Líquidos magnéticos funcionalizados concentrados: compressão osmótica e estrutural local do coloide

The Magnetic Fluid (MF) or Ferrofluids (FF) are colloidal dispersions of nanoparticles dispersed in a liquid carrier. This nanomaterial presents a combination of liquid properties and magnetic properties, which enables these materials respond to a magnetic field and may thus be contained, displaced, deformed and controlled. The reflection of this are the numerous applications for these materials, particularly in the areas of technology, environmental and biomedical. Successful in peptization of MF is inextricably linked to achieving thermodynamic stability being acquired when there is the inclusion of repulsive forces offsetting the attractive interactions of the system. The ferrofluids studies in this work are composed of functionalized nanoparticles with tartrate. The tartrate of type polyelectrolyte is a molecule that allows adsorption of the molecules beyond the surface of the nanoparticles leads to the formation of electrical charges. Therefore, the thermodynamic stability here is obtained by forming a steric repulsion derived from the molecules along with the loads from the carboxylate groups (COO-). When adjusted to a physiological pH (pH = 7) Our colloid shows the formation of clusters coming from the formations of hydrogen bonding that occurs between tartrate molecules adsorbed with solvent and / or free tartrate molecules. With the objective of analyze the local structure of the functionalized colloidal, our sample Ferrofluid with tartrate were submitted to an osmotic compression process, in which was used a polyethylene glycol polymer bath, PEG 35000, at different concentrations of 3%, 6% and 18%. For each sample taken bath was conducted measurements to determine the concentrations of metals (Fe and Co) of the samples. The samples with high viscosity was used to Archimedes balance to determine density. Scattering measurements of x-ray to Low angle (SAXS) were performed for all concentrated samples. For the PEG 3% for structure formation with a correlation peak aq = 0,011Å-1, with distance between 57.1 nm particle.