Surface/interface order in liquids with electrostatic correlations: X-ray scattering studies

技术摘要水和含有溶解离子的水溶液在自然界中普遍存在，水溶液与表面之间的静电相互作用驱动着生物、化学、地质和环境科学、食品技术等领域的许多重要现象。溶解离子在界面附近表现出许多显著的行为。例如，据预测，与溶液接触的带电表面可能会吸引如此多的溶解的多价离子，使它们聚集在有序的界面层中，从而不仅中和表面电荷，而且增加多余的相反电荷(电荷反转)。同样，疏水表面被反直观地预测当与离子溶液接触时会吸引溶解的负离子。这些和其他新的现象将用同步加速器X射线散射来研究，以直接了解离子是如何排列的，以及在什么条件下。从所提出的研究中获得的知识最终将有助于为实际应用设计具有特定表面/界面行为的系统。该项目将在跨学科环境中培训研究生，并给予他们使用同步加速器设施的经验。与液体相关的主题将被纳入本科生和研究生课程以及网络传播的教材中。*非技术摘要*水经常含有溶解离子，离子溶液与其他材料的相互作用导致了生物、化学、地质和环境科学、食品技术等许多关键现象。溶解离子被认为在固体表面附近以显著和意想不到的方式表现。例如，据预测，当带电的固体表面变湿时，它吸引的溶解离子可能会形成有点像晶体的有序层，因此填充了如此多的离子，以至于界面实际上最终产生了净相反的电荷。同样，理论上预测，排斥水的表面在接触离子溶液时会吸引负离子，这完全是违反直觉的。这些和其他新的现象将通过使用同步加速器X射线来研究，以直接观察溶解离子是如何排列的以及在什么条件下。从拟议的研究中学到的东西最终可能有助于为实际应用设计具有特定特性的系统。该项目将在跨学科环境中培训研究生，并给予他们使用同步加速器设施的经验。与液体有关的主题将被纳入本科生和研究生课程以及网络传播的教材。

****Technical Abstract****Water, and aqueous solutions containing dissolved ions, are ubiquitous in nature, and electrostatic interactions between aqueous solutions and surfaces drive numerous crucial phenomena in biology, chemistry, geology and environmental science, food technology, etc. Dissolved ions are thought to behave in a number of remarkable ways near interfaces. For example, it is predicted that a charged surface in contact with a solution may attract so many dissolved multivalent ions that they will pack into a ordered interfacial layer, thus not just neutralizing the surface charge but adding an excess of the opposite charge ("charge inversion"). Again, hydrophobic surfaces are counterintuitively predicted to attract dissolved negative ions when in contact with ionic solutions. These and other novel phenomena will be studied using synchrotron X-ray scattering to see directly how the ions are arranged and under what conditions. The knowledge gained from the proposed studies will ultimately help design systems with specific surface/interface behaviors for practical applications. This project will train graduate students in an interdisciplinary environment and give them experience in the use of synchrotron facilities. Liquids-related topics will be incorporated into undergraduate and graduate courses and web-disseminated teaching materials.****Non-Technical Abstract****Water often contains dissolved ions, and the interaction of ionic solutions with other materials is responsible for many crucial phenomena in biology, chemistry, geology and environmental science, food technology, etc. Dissolved ions are thought to behave in remarkable and unexpected ways near solid surfaces. For example, it is predicted that when a charged solid surface becomes wet, the dissolved ions it attracts may form an ordered layer somewhat like a crystal, thus packing in so many ions that the interface actually ends up with a net opposite charge. Again, surfaces that repel water are theoretically predicted to attract negative ions when they touch ionic solutions, which is completely counterintuitive. These and other novel phenomena will be studied by using synchrotron X-rays to look directly at how dissolved ions are arranged and under what conditions. What is learned from the proposed studies may ultimately help design systems with specific properties for practical applications. This project will train graduate students in an interdisciplinary environment and give them experience in the use of synchrotron facilities. Liquids-related topics will be incorporated into undergraduate and graduate courses and web-disseminated teaching materials.