Nuclear magnetic resonance studies of disordered materials

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Advancement in materials science depends on reliable methods of structural characterization. The disordered nature of many classes of solid materials makes it difficult to obtain a detailed understanding of the atomic-level structure. Recent developments in nuclear magnetic resonance (NMR) theory and instrumentation have greatly expanded the range of elements that can be studied by this technique. Indeed, NMR is rapidly becoming a routine approach for the structural characterization of a wide variety of advanced materials, including glasses, ceramics, cements, polymers and porous materials. The broad objective of this proposal is to build on newly developed techniques in NMR designed to identify longer-range structure in disordered solids. Central to these efforts are methods which exploit interactions between two nuclei as a direct probe of distance. This approach provides more direct information on medium-range order than chemical shifts, which are only indirectly related to neighbouring atoms. No other experimental technique is able to map atomic connectivities as directly as NMR. This work will lead to more detailed correlations between atomic-level organization and bulk properties, thus opening the door to a more comprehensive description of glass structure and providing a critical link between structure and function.  Although generally applicable techniques are sought, initial applications will target borate-based glasses of varying complexity, and paramagnetic organometallic materials, both of which represent well-studied but incompletely understood systems with far-reaching implications in commercial production and the development of new materials. In addition to technique development and exploration, these studies will yield unique and fundamental insight into the nature of the glassy state, providing structural information essential to the rational design of high-performance glasses for applications ranging from optical lenses to nuclear waste immobilization.