Recent developments in surface analysis, computer simulations using quantum mechanical and empirical methods, and advanced techniques in electron microscopy now allow the accurate characterization and modeling of interface properties between nanoparticles and their immediate atomic-scale environment. These properties encompass the structural relationships between both phases, the stability of nanomaterials in their respective hosts, the chemistry in and near the interface, electron transfer mechanisms across the interface, and magnetic ordering in the nanoparticle, as well as in the near-interface region of the host matrix. These interface properties have a critical influence on the reactivity and the environmental behavior of nanoparticles. Therefore, their fate in the environment cannot be understood if only size and structure are considered. We propose to apply this combination of newly-developed experimental and theoretical capabilities to a variety of research topics that collectively focus on the important role of nanoparticle interfaces in natural systems, such as the formation of metal particles on sulfide and oxide surfaces and their incorporation into the bulk, transport of metal-bearing nanoparticles in atmospheric particulates and groundwater colloids, and to biomineralization processes.
Broader impact: This new initiative at the University of Michigan is also supported by the development of new graduate and undergraduate courses to stimulate student interest in this field. We are in the process of developing new courses in environmental geochemistry, environmental mineralogy, mineral surface science, computational methods, nuclear materials, and radioactive waste management. A number of undergraduate and graduate students from different disciplines, such as mineralogy, geology, applied physics, chemistry, nuclear engineering, materials science, and chemical engineering are expected to be involved in the projects proposed. In addition, we plan to develop a public exhibition on nanoparticles in the Museum of Natural History at the University of Michigan. The exhibit will emphasize the broad applicability of nanogeoscience to diverse areas of great public interest, such as medicine (bone and tooth growth), development of geomimetic materials, new methods for metal exploitation and mineral processing, and release and transport of environmentally hazardous materials. The museum is regularly visited, not only by university students, but also by students from the local middle and high schools, and by the general public.
