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

离子液体（ILs）具有有趣的物理化学性质，包括低挥发性，高热稳定性，高CO2溶解度和选择性，以及独特的溶剂化特性，使其成为涉及CO2捕获，催化和胶体颗粒分散的有希望的候选者。该合作项目将结合实验和分子模拟，旨在了解界面水在ILs和固体表面之间的界面中的作用。研究界面水对固体表面电气化和界面il结构的作用，并研究其对il -固体界面CO2吸附的影响。本研究旨在研究水对il界面结构的影响，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，这对于解决目前关于水对il界面影响的争议至关重要。多方面的实验表征（例如，衰减全反射傅立叶变换红外光谱，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- il界面结构和这些界面上气体吸附的影响的高质量数据和机制见解。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电气化和界面il的结构，云母将被用作固体表面，以测试水通过有效溶解表面离子使固体表面通电的假设，并通过水- il耦合影响il的自组装。为了研究水如何影响IL-solid界面上CO2的吸附，二氧化硅将被用作固体表面，因为它与包括CO2捕获和催化在内的应用相关。从该项目中获得的见解可以通过控制含水量来定制固体- il界面和这些界面上的气体吸附。除了培养研究生和开发新课程，研究人员计划为来自代表性不足群体的本科生提供研究机会，并与匹兹堡大学的工程推进小学教育（ENGAGE）项目和弗吉尼亚理工大学的工程多样性增强中心（CEED）合作，为K12学生提供拓展活动。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的智力评估被认为值得支持优点和更广泛的影响评审准则。

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.