CAREER: Exploration of Negative Thermal Expansion Materials: from Basic Properties to Formation of Composites.

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TECHNICAL EXPLANATIONThis CAREER proposal is aimed at developing materials and composites and a fundamental understanding of thermal expansion phenomena. The goal is to achieve the following scientific objectives: (1) To gain a fundamental understanding of factors that influence the expansion and phase transition behavior of negative thermal expansion (NTE) materials through the preparation and characterization of new NTE compounds such as those belonging to the scandium-tungsten-oxide (Sc2W3O12) family; (2) to characterize the high-pressure behavior of these materials; and (3) to prepare NTE/polymer composites with tailored thermal expansion properties. Student training will involve the exploration of novel low temperature synthesis routes, and the use of cutting edge characterization techniques like high-pressure studies in diamond cells and synchrotron work. At the same time, the intriguing topic of "Materials that shrink when heated" will be used to enhance the public image of materials chemistry through outreach activities.NON-TECHNICAL EXPLANATIONThermal expansion is an important property from the standpoint of engineering applications. Mismatches in thermal expansion between two materials that are bonded together (e.g. tooth fillings, metal and concrete in the construction business) can result in cracks, or separation at interfaces. It would be beneficial to control and in many cases minimize the thermal expansion of materials. Negative thermal expansion (NTE) materials are particularly promising for reducing the expansion of other materials when used in composites. This project will also provide opportunities to teaching the general public about the exciting possibilities of Materials Chemistry. Materials that shrink when they are heated have many important applications that can be easily explained to both children and adults, which will help to excite the next generation of scientists.