Synthesis, Design and Function in New Materials Chemistry

点击翻译按钮获取中文摘要

An essential goal of Materials Chemistry is to understand how materials are formed, why they have their individual properties, and from this how one can set about improving them and also designing new materials for a given function. It is universally held that to do this one must first obtain a working knowledge of how materials are structured, from the mm scale of the engineer down to the atomic level (1/10millionth mm). The complete materials chemist must be able not only to make materials with specific properties and set them into action, often under hostile operating conditions of high-pressure and temperature and corrosive chemical conditions, but must also be able to determine their structure and chemical reactivity in order to devise a working structure-properties model of the material and the chemical processes under study. Our ultimate aim is to use such models developed via a combined theoryexperimental approach to guide materials chemists in their quest to improve existing teachnological materials or design and create completely new compounds for advanced technology applications.To achieve this goal requires cutting edge science at the frontier between theoretical predictions of new compounds and their properties, synthesis and characterisation of their behaviour, and in situ studies of how the materials behaviour under realistic operating conditions of their synthesis and ultimate applications. We must master the wide range of extreme chemical and high temperature-high pressure conditions that will be encountered, in what might be termed the materials chemist's cooking pot : Many materials are required to perform to a high standard of mechanical or chemical resistance within chemically corrosive high pressure and temperature aqueous or gaseous environments. Examples are cements used to seal deep oilwells, advanced ceramics used in exhaust catalytic convertors, ultrahard materials used for high-speed drilling, microporous solids used in catalysis and ion exchange reactions; and even natural materials encountered under the extreme high-P,T conditions of the deep Earth and other planets. Study of such exotic materials is far from academic; it has already yielded new super-hard materials such as cubic boron nitride and synthetic diamond: new semiconductors, superconductors, intercalated compounds and high-hardness materials are predicted to result from such studies. We must study the chemical and structural changes occurring within existing and new materials as they are being formed or during their actual working conditions. We do this in the laboratory using spectroscopy, or at synchrotron and neutron sources by directing intense beams of X-rays (or neutrons) onto and inside the material, and rapidly collecting and analysing the scattered light to give us direct information on its changing structure and electronic and bonding properties. X-rays derived from a synchrotron source are sufficiently intense and penetrating that they pass through the container device and the material under study to give structural and chemical information and mapping of the inside of the sample. We devise and develop new methods for imaging such materials. We also design new environmental cells for in situ materials studies in the laboratory and at synchrotron and neutron sources, combined with theoretical predictions that guide the development of the synthesis and in situ experiments. The theory-experiment interaction feeds the next cycle of new materials creation and understanding