Berlin 2018 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 45: Charged Soft Matter, Polyelectrolytes and Ionic Liquids I

CPP 45.5: Talk

Wednesday, March 14, 2018, 12:15–12:30, C 243

The influence of co-solutes on the chemical equilibrium - a Kirkwood-Buff theory for ion pair formation processes in ternary solutions — •anand narayanan krishnamoorthy, christian holm, and jens smiatek — Institute for Computational Physics - University of Stuttgart

We present a theoretical framework for ternary solutions in order to describe the influence of co-solute species on the chemical equilibrium of ion pair formation. The theory relies on the use of Kirkwood-Buff integrals and the introduction of a local/bulk partition model. We can show that either ion pair formation or ion dissociation is favored with regard to a more pronounced co-solute accumulation around the corresponding ion state. The co-solute molecules can be either charged or uncharged and the theory is applicable for ideal and weakly non-ideal solutions in combination with low ion concentrations. The corresponding implications of our theory are useful in order to optimize the efficiency of electrolyte solutions in electrochemical applications. All theoretical results are verified by atomistic molecular dynamics simulations of sodium chloride ion pairs in dimethylacetamide (DMAc)/water mixtures.