Ionic-Liquid Surface Structure: Informing Applications through Dynamical Measurements

US Collaborator: Prof T K Minton, Montana State University.
We aim to enhance the fundamental understanding of ionic-liquid (IL) surface structure and to relate this new insight to some key sustainable applications of ILs. Inelastic and reactive scattering of atoms and molecules from liquid surfaces will be developed as a new, chemically specific analytical probe. Two distinct and complementary experimental approaches will be pursued, based on laser-photolysis-laser-spectroscopic probing and molecular-beam scattering. The laser-based method is well matched to higher-throughput screening of surface composition of a range of samples, while molecular-beam scattering will provide additional information on surface structure for selected liquids. In combination, they will probe the degree of surface segregation in custom-synthesized, high-purity ILs of recognized practical interest. The research will proceed in stages of complexity and degree of risk. The first phase will address unanswered structural questions for pure ILs representative of important families of large organic cations combined with a range of anions. The second will investigate surface enrichment in IL mixtures. The third will explore the relationship between the surface structures of IL solutions and their applications in catalysis, through supporting measurements of kinetics and product state distributions. The final phase will enter the uncharted area of the surface properties of liquid-crystalline ILs. The interpretations will be supported throughout by molecular dynamics (MD) simulations and selected QM/MM scattering calculations.
The results will have scientific impact on several levels. We expect to directly influence the future programs of scientists already engaged in closely cognate studies of collision dynamics at liquid or related surfaces. Our results will also be of direct interest to a broader community who have been using other methods to analyze liquid surfaces, or characterizing them through MD simulations. Finally, and most broadly, the results will inform the very large research community working on the synthesis of new ILs and the development of their future applications.
The investigators represent a unique combination of established expertise in the chemical synthesis and catalytic applications of ILs (Slattery and Bruce; York, UK), experimental measurements of scattering dynamics using laser-based (McKendrick and Costen; Heriot-Watt, UK) or molecular-beam (Minton; Montana State, USA) methods, and theoretical modeling of gas-liquid interactions (Schatz; Northwestern, USA). The proposed program is founded on extensive exchanges of staff, broadening their experience and promoting exchanges of ideas and complementary technical expertise.
The fundamental new insight that we will generate is most likely to be exploited through its enabling role in the design and optimization of IL materials for numerous "environmentally friendly" applications. The most direct impact will be on processes involving transport through the gas-liquid interface, including various forms of catalysis. The staff employed will receive an exceptional and unusually diverse training in modern research methods. They will have ample opportunities to develop broader, transferable skills and enjoy the cultural benefits of international exchange, equipping them to contribute to the future growth or creation of high-technology companies. Outreach will be actively promoted through the creation of a new website, and associated YouTube Channels. These will promote both the results of the proposed on ILs and their broader uses in general. Downloadable objects will be suitable for tutorials and other teaching tools. The web site will be hosted at MSU.. It will be populated with material aimed at a number of levels, ranging from the specifically interested scientific experts, through a scientifically-inclined audience, to school (K-12) teachers and the lay public.

The most direct link from our work to sustainable chemistry will be through informing the creation of new IL materials for "environmentally friendly" applications. ILs have already been used on an industrial scale in a number of sustainable processes, such as the BASIL process for the production of alkoxyphenylphosphines (BASF); isomerisation of 3,4-epoxybut-1-ene to 2,5-dihydrofuran (Eastman), or the dimerisation of alkenes (IFP). The proposed work is most likely to lead to societal and economic benefits on a longer timescale, but if direct commercial opportunities should arise they would be pursued via the HWU Research and Enterprise Services unit, York's Research Innovation Office, and/or through the Technology Transfer Office at MSU.
Our goal is to develop a highly integrated, multidisciplinary training program with shared mentorship aimed at creating new scientists whose expertise spans modern synthetic chemical methodology; forefront computational modeling; and laser, molecular-beam, vacuum, electronic-data capture and data-processing technologies. Students and post-docs in the individual groups at the participating institutions will receive individual instruction and guidance from their primary advisor and from other senior students and post-docs in the group. In addition, groups will hold regular meetings in which research plans and progress are discussed.Through the collaborative exchanges, all graduate students and post-docs will have an opportunity to be co-mentored by another senior investigator, broadening their perspective on research and ensuring the multidisciplinary nature of the training. Our educational program will provide these students and post-docs with a breadth of knowledge that will equip them for ongoing research and to go out as engaged scientists and educators able to contribute to scholarly activities at all levels. They will be ideally suited to contribute to the growth or creation of high-technology companies, enhancing innovative capacity and consequently increasing business revenues. The students at MSU and HWU and the PDRAs at HWU and York will be encouraged to engage in undergraduate teaching (within the contractual limits set by EPSRC) and we would continue to provide opportunities for UK undergraduate students to undertake compulsory research project work in these areas.
Outreach will be actively promoted through the creation of a new website, and associated YouTube Channels. These will promote both the results of the proposed research on ionic liquids and their broader uses in general, with the intent that downloadable objects will be suitable for tutorials and other teaching tools. It will be populated with material aimed at a number of levels, ranging from the specifically interested scientific experts, through a scientifically-inclined audience (e.g., undergraduates, college and university teachers, curious members of the educated public), to school teachers and the lay public.