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

技术说明本职业计划旨在开发材料和复合材料以及对热膨胀现象的基本理解。 本论文的主要研究目标是：（1）通过制备和表征新型负热膨胀（NTE）化合物，如氧化钪钨化合物，对影响NTE材料膨胀和相变行为的因素有了基本的认识（Sc_2W_3O_12）族的NTE/聚合物复合材料;（2）表征这些材料的高压行为;（3）制备具有定制热膨胀性能的NTE/聚合物复合材料。学生培训将涉及新的低温合成路线的探索，以及使用尖端的表征技术，如金刚石细胞和同步加速器工作中的高压研究。与此同时，还将以“加热时会收缩的材料”为主题，通过宣传活动，提高材料化学的公众形象。非技术说明从工程应用的角度来看，热膨胀是一个重要的性质。粘合在一起的两种材料（例如牙齿填充物、建筑行业中的金属和混凝土）之间的热膨胀不匹配可能导致界面处的裂缝或分离。控制材料的热膨胀并且在许多情况下使材料的热膨胀最小化将是有益的。负热膨胀（NTE）材料在用于复合材料时特别有希望减少其他材料的膨胀。该项目还将提供机会，向公众讲授材料化学令人兴奋的可能性。加热时收缩的材料有许多重要的应用，可以很容易地向儿童和成人解释，这将有助于激发下一代科学家的兴趣。

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.