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Thermodynamics of Densely Charged Media

Investigator: Amir Abolhasani Niazi -- Advisor: Ahmed Ismail

Several different processes will be studied in detail as part of this research. The initial step will simulate the dynamics of an ionic liquid coming into contact with a substantial amount of structural water released by lignocellulosic material by constructing thin slabs, representing water and the ionic liquid, in contact with one another, and observing the mixing process, if any, as a function of time. The relevant properties to be observed include both the location of the interface, as well as the formation of solvation shells around the individual cations and anions in the ionic liquid. In addition, since other dissolved materials may be present in solution, further calculations will be performed to determine the dynamics as a function of the concentration of dissolved species (both aqueous and in the ionic liquid).< /br> The second phase of the study will determine the stability envelope of the ionic liquid with respect to the concentration of water. At low water concentrations, screening effects may prevent aggregation of water and the formation of stable solvation shells; however, as water concentration increases, one expects to find that the system transforms, such that the ionic liquid becomes the solute in an aqueous solution instead of water being dissolved in the ionic liquid. By monitoring properties of the solution, such as the radial distribution function as well as diffusion constants, we can determine the critical concentration of water at which the phase behaviour of the composite system begins to change. Determining these critical concentrations at which this transition occurs for different ionic liquids will assist in the determination of an optimal ionic liquid for processing of lignocellulosic materials. If a sufficiently broad array of ionic liquids is examined, the results could be used to determine the relationship between the molecular structure of the ionic liquids and its phase behaviour in solution.< /br> The selection of the specific ionic liquids to be studied will be determined in consultation with the experimental groups within the TMFB cluster, as well as the groups working on ab initio force fields and molecular mechanics of ionic liquids.