Water confinement frequently occurs in various chemical and biological systems as a result of the close proximity between water molecules and the interface. The confinement dramatically affects the properties of water and thus of its dissolved solutes. In this study, the vibrational dynamic of an ionic solute inside an aqueous reverse micelle is investigated via FTIR, ultrafast IR pump-probe, and 2D-IR spectroscopies. The 2D-IR experimental results allow us to unambiguously locate the ion in two distinct regions of the reverse micelle, namely interface and water pool. In addition, these results show a significant slowdown in the hydration as well as vibrational relaxation dynamic of the nano-confined ion when compared to bulk water. Moreover, the magnitude of the slowdown in dynamic of either of the processes is found to be highly dependent on the size of the nano-water pool. These results provide new insights of the hydration dynamics of ions in nano-confined aqueous environments.

Ion's perspective of nanoconfinement in water pools: A 2D IR investigation

246th National Meeting (2013)

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