Many applications of ionic liquids (ILs), such as electrolytes for fuel cells, require an understanding of their properties when mixed with water. Using pulse-gradient spin-echo NMR measurements,[1] we will present results on the self-diffusion of IL cations, anions and water. We investigated two systems: water in hydrophobic P14+/NTf2- and water in hydrophilic P14+/CF3SO3-. Self-diffusion coefficients for cations, water and anions increase with increasing temperature and water concentration. Water exhibits anomalous self-diffusion in the ILs with increasing concentration.[2] Our investigation of the temperature dependence for water self-diffusion shows that the mechanism of water transport changes with temperature as well as with concentration. This work was supported in part at BNL by the U.S. DOE Office of Basic Energy Sciences under contract # DE-AC02-98CH10886.[1] Tokuda, H.; et al., J. Phys. Chem. B 2005, 109, 6103. [2] Rollet, Anne-Laure, et al., J. Phys. Chem. B (2007), 111, 11888-11891.

Temperature dependence of self-diffusion coefficients in ionic liquid/water systems

239th National Meeting (2010)

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