Carbon Combustion Synthesis in Patterned Precursor Media

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0933140LitvinovCarbon combustion synthesis of micro and nanostructured complex oxides appears to offer a simple and efficient method for making complex micro- and nanostructured oxides to be used in biomedical imaging, drug delivery, data storage, biosensors, memory devices, nanoelectronics, and energy storage. To respond to the demand for such new materials, many synthesis approaches have been developed with varying complexities, materials quality, production costs and efficiency. Often, however, relative complexity, high reactant costs, and environmental issues of by-product disposal limit large-scale applications. In carbon combustion synthesis, nanoparticulates are formed from stoichiometric powder mixtures of simple oxides with nano graphite in a self-propagating reaction wave sustained by exothermic oxidation of carbon. Synthesis occurs on a time scale of several seconds with the thermal front propagation velocities in the range of 0.1 to 3 mm/s; preliminary data on a thin-film version of the process show less than 1sec conversion times. The technology carries a significant promise for simplicity, low reactant costs, and no other byproducts than carbon dioxide.The goal of this experimental and modeling project is to gain insight into the mechanisms of phase nucleation and growth and to apply the knowledge for control of the material properties. The work is particularly innovative in that, for the first time, combustion synthesis in patterned precursor media will be investigated. An efficient toolset for real-time synthesis monitoring and post-synthesis characterization of reaction products will be developed and used for the experiments. To interpret the data and to predict the impacts of carbon dioxide release and the counterdiffusion of oxygen on thermal energy transport during carbon combustion synthesis and on the properties of the products, a computer model will be developed. The target use is efficient synthesis of magnetic nanoparticles with precision-controlled properties for applications in biosensors, data storage, and medical imaging, using cobalt ferrite as a model system. In addition to the potential technological impacts, findings of the program will be integrated into the existing materials-related courses taught by the PI. A diverse set of graduate and undergraduate students participating in the program will be at the forefront of a fascinating scientific field with broad industrial potential.