New class of colloidal systems

Scientists have identified a new class of colloidal systems, which are homogeneous dispersions of highly dissimilar constituents, involving inorganic solvents. A team of researchers, led by scientists at the University of Chicago and the Argonne National Laboratory , has identified a new class of colloidal systems involving inorganic solvents'a discovery that could offer new applications for nanotechnology and better functional materials. Colloidal systems are all around us in nature, from milk to blood, and in everyday items, from colored plastics to wall paints. Colloidal systems are a mixture in which one substance is uniformly distributed throughout the second; although the naked eye cannot see the individual particles in a colloid, these particles, especially nano-size crystals, can be identified with certain powerful microscopes. In contrast, a true solution like plain sugar dissolved in water is one in which one substance is completely dissolved in the other. In a research report published in the journal Nature , the team showed that nanoparticles form stable colloids in various molten inorganic salts, but the stability of these colloids cannot be explained by traditional mechanisms. Instead, theoretical analysis and modeling suggest that a layer of surface-bound solvent ions causes the partial ordering of molten salts around each nanoparticle, preventing the aggregation of the systems.