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arXiv · 0904.0717

Glasslike Behavior in Aqueous Electrolyte Solutions

David A. Turton·Johannes Hunger·Glenn Hefter·Richard Buchner·Klaas Wynne
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Abstract

When salts are added to water, the viscosity generally increases suggesting the ions increase the strength of the water's hydrogen-bond network. However, infrared pump-probe measurements on electrolyte solutions have found that ions have no influence on the rotational dynamics of water molecules implying no enhance-ment or breakdown of the hydrogen-bond network. Here we report optical Kerr-effect and dielectric relaxa-tion spectroscopic measurements, which have enabled us to separate the effects of rotational and transitional motions of the water molecules. These data show that electrolyte solutions behave like a supercooled liquid approaching a glass transition in which rotational and translational molecular motions are decoupled. It is now possible to understand previously conflicting viscosity data, nuclear magnetic resonance relaxation, and ultrafast infrared spectroscopy in a single unified picture.

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David A. Turton, Johannes Hunger, Glenn Hefter, Richard Buchner, Klaas Wynne. 2009-04-04. Glasslike Behavior in Aqueous Electrolyte Solutions. https://doi.org/10.1063/1.2906132

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