Investigations of ionic liquid - solute systems by surface sensitive spectroscopic techniques - part of the initiative "Shaping micro- and macroscopic properties of ionic liquid-solute systems"

我们建议用表面敏感方法对离子液体表面的分子结构进行实验研究。目标是通过确定离子液体的表面结构来确定其热力学性质，并验证模拟结果。我们能够用中性碰撞离子散射光谱(NICISS)的方法直接测定液体表面的浓度深度分布。浓度深度分布给出了不同物种的表面过剩。已知表面张力，利用吉布斯方程即可确定化学势。化学势通常是优化化学过程所需的信息。研究的一个重要前提是控制液体表面的清洁度。表面敏感方法特别适用于检测表面活性杂质的存在。测量被调查物质的表面张力，我们将能够获得控制表面清洁度的系统的数据。尽管我们的项目将对整个优先计划产生普遍的好处，但它将在4个小组之间密切合作进行。该项目对进一步了解离子液体本身的结构-性质关系是一项重要贡献，这四个研究小组将通过参与由化学工程师、物理学家和化学家组成的跨学科网络而互惠互利。产生物理化学数据的新方法通过现有方法得到验证，从已知纯度的离子液体中获得的大量数据在网络中共享，从而使合作伙伴能够从科学的各个方面剖析结果：基础和理论以及技术和实验。

We propose to investigate experimentally the molecular structure of the surface of ionic liquids with surface sensitive methods. The goals are to determine thermodynamic properties of ionic liquids by determining their surface structure and to validate the results of simulations. We are able to determine directly concentration depth profiles of liquid surfaces with the method neutral impact collision ion scattering spectroscopy (NICISS). The concentration depth profiles yield the surface excess of the different species. Knowing the surface tension and making use of the Gibbs equation the chemical potentials can be determined. The chemical potential is an information in general required for optimizing chemical processes. An important prerequisite for the investigations is the control of the cleanliness of the liquid surfaces. Surface sensitive methods are especially suitable for detecting the presence of surface active impurities. Measuring the surface tension of the investigated substances we will be able to gain data of systems with controlled cleanliness of the surface. Even though our project will be of general benefit for the entire priority program, it will be carried out in close cooperation between 4 groups. The project is an essential contribution for a further understanding of ionic liquid structure-property relationships in its own right, the four research groups will mutually benefit from participating in an interdisciplinary network of chemical engineers, physicists, and chemists. New methods of generating physico-chemical data are validated with existing methodology, and the large set of data obtained from ionic liquids of known purity is shared within the network, thus enabling the partners to dissect the results from a cross-section of science: fundamental and theoretical as well as technological and experimental.