Synchrotron X-ray studies on atomic structures of matter: self-assembled monolayers and environmental arsenic chemical speciation

物质原子结构的同步加速器 X 射线研究：自组装单分子层和环境砷化学形态

• 批准号: 327159-2006
• 负责人: Jiang, DeTong
• 金额: $ 1.85万
• 依托单位: University of Guelph
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2007
• 资助国家: 加拿大
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=366200
• 关键词: Synchrotron; ray; studies; atomic; structures

This research proposal concerns with experimental studies on atomic structures of materials. Two classes of materials are of our interest. The first is called self-assembled monolayers, or SAMs. These are the films formed on solid substrates, with the thickness of a single molecule. They typcially consist of hydrocarbon molecule chains with one end chemically anchored on the solid substrate surface and the other end left free standing or can be further modified to have a variety of interesting macroscopic properties, such as wetting, corrosion resistivity, and etc. Our interest is at the formation mechanisms of such films and hence to be able to form the new types with targeted material properties following a knowledge-based design strategy rather than the traditional trial and error approach. The second class of material of our interest is the environmental arsenic species related to anthropogenic activities. The environmental impact of arsenic and its endemic and chronic poisoning effects have been documented all over the world. To develop effective environmental remediation strategies, the molecular level understanding of the arsenic species is necessary. Our approach to address aforementioned subjects is based on using X-rays generated by a kind of electron or positron accelerators called synchrotrons, for example the newly commissioned third generation synchrotron, the Canadian Light Source (Saskatoon, SK), will be one of the primary tools for this study. Other facilities to be used include the Advanced Photon Source (Argonne National Laborotary, Chicago IL) and the Synchrotron Radiation Center (Univ. Wisconsin-Madison). The synchrotron X-rays are much brighter than that from the conventional X-ray machines, also the synchrotron X-rays are tunable in their wavelengths, another property that common X-ray machines do not have. These properties make it possible to have very intense and highly collimated X-ray beams over a wide range of wavelength to be applied for materials science studies.

这项研究计划涉及材料原子结构的实验研究。我们对两类材料感兴趣。第一种称为自组装单分子层，或SAMs。这些是在固体基底上形成的膜，具有单个分子的厚度。它们通常由烃分子链组成，其一端化学锚定在固体基材表面上，另一端保持自由站立，或者可以进一步改性以具有各种感兴趣的宏观性质，例如润湿性、耐腐蚀性、我们的兴趣在于这些膜的形成机制，因此能够在了解-设计策略，而不是传统的试错法。我们感兴趣的第二类材料是与人类活动有关的环境砷物种。砷对环境的影响及其地方性和慢性中毒效应已在世界各地被记录在案。为了制定有效的环境修复策略，分子水平上的砷物种的理解是必要的。我们解决上述主题的方法是基于使用由一种称为同步加速器的电子或正电子加速器产生的X射线，例如新委托的第三代同步加速器、加拿大光源（萨斯卡通，SK），将是本研究的主要工具之一。其他设施包括先进的光子源（阿贡国家天文台，芝加哥IL）和同步辐射中心（威斯康星大学麦迪逊分校）。同步加速器X射线比传统的X射线机亮得多，而且同步加速器X射线的波长是可调的，这是普通X射线机所不具备的另一个特性。这些特性使得在很宽的波长范围内具有非常强和高度准直的X射线束成为可能，以应用于材料科学研究。