Collaborative Research: Structure and Thermodynamics of Ionic Liquids at Solid Surfaces: the Return of Water

离子液体具有低挥发性、高热稳定性、高CO2溶解度和选择性以及独特的溶剂化特性，在CO2捕集、催化和胶体粒子分散等领域具有广阔的应用前景。这个合作项目将结合联合收割机实验和分子模拟，旨在了解界面水在离子液体和固体表面之间的界面的作用。研究了界面水对固体表面带电和界面离子液体结构的影响，以及它对离子液体-固体界面CO2吸附的影响。该研究旨在探讨水对离子液体界面结构的作用，并解决界面区表面带电，水吸附和离子自组装之间的三向耦合，这对于解决水对固体-离子液体界面影响的现有争议至关重要。多方面的实验表征（例如，衰减全反射傅里叶变换红外光谱、X射线反射率和中子反射率）将与计算机模拟相结合，以获得关于水对固体-离子液体界面结构和这些界面处的气体吸附的影响的高质量数据和机理见解。这将有助于解决文献中的争议，并为二氧化碳捕获等应用提供指导。为了研究水如何影响固体表面的带电和界面离子液体的结构，云母将被用作固体表面来测试假设，即水通过有效溶解表面离子来使固体表面带电，并通过水-离子液体耦合来影响离子液体的自组装。为了研究水如何影响IL-固体界面处的CO2吸附，将使用二氧化硅作为固体表面，因为其与包括CO2捕获和催化的应用相关。从该项目中获得的见解可以通过控制水含量来定制固体-IL界面和在这些界面处的气体吸附。除了培养研究生和开发新课程外，研究人员计划与匹兹堡大学的工程推进小学教育项目（ENGAGE）和工程多样性增强中心（CEED）合作，为来自代表性不足群体的本科生提供研究机会，并为K12学生开展推广活动该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估的支持。

Ionic liquids (ILs) have interesting physicochemical properties, including low volatility, high thermal stability, high CO2 solubility and selectivity, and unique solvation characteristics, making them promising candidates for applications involving CO2 capture, catalysis, and dispersion of colloidal particles. This collaborative project will combine experiments and molecular simulations aiming to understand the role of interfacial water at the interface between ILs and solid surfaces. The role of interfacial water on the electrification of solid surfaces and the structure of interfacial ILs will be investigated and its impact the CO2 adsorption at IL-solid interfaces will be studied. The proposed research aims to investigate the role of water on the interfacial structure of ILs and address the three-way coupling among surface electrification, water adsorption and ion self-assembly in the interfacial zone, which is crucial for resolving existing controversies on the effect of water on solid-IL interfaces. A multi-faceted experimental characterization (e.g., attenuated total reflectance Fourier transform infrared spectroscopy, X-ray reflectivity, and neutron reflectivity) will be integrated with computer simulations to obtain high-quality data and mechanistic insights on the effect of water on the structure of solid-IL interfaces and gas adsorption at these interfaces. This will help settle the controversies in the literature and provide guidelines for applications such as CO2 capture. To investigate how water affects the electrification of solid surfaces and the structure of interfacial ILs, mica will be used as the solid surface to test the hypotheses that water enables electrification of solid surfaces by effective dissolution of surface ions and impacts self-assembly of ILs via water-IL coupling. To investigate how water impacts the CO2 adsorption at IL-solid interfaces, silica will be used as the solid surface because of its relevance to applications including CO2 capture and catalysis. The insights gained from this project may enable the tailoring of solid-IL interfaces and gas adsorption at these interfaces by controlling the water content. In addition to training graduate students and developing new courses, the investigators plan to offer research opportunities to undergraduate students from underrepresented groups and pursue outreach activities to K12 students in collaboration with the Engineering Advancing Grade-school Education (ENGAGE) program at the University of Pittsburgh and the Center for the Enhancement of Engineering Diversity (CEED) at Virginia Tech.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.