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Abstract
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Molecular dynamics simulations are done on aqueous mixtures of ionic liquids (ILs) [Emim][MeSO4] and [Bmim]
[MeSO4]. At low water contents, the water is confined in ion cages, while at high water contents, two stable
phases containing one big cluster of water molecules and an IL network are formed. Water molecules and anions
aggregate more around the imidazolium ring of [Bmim][MeSO4] than [Emim][MeSO4]. The same tendency is
observed for hydrogen bond (HB) formation between water and IL. The HB dynamics accelerates with increasing
the water content of IL, which is shown to be due to the increased diffusion coefficient of all species with
increasing the water content. An examination of the global dynamics of the system, investigated in terms of ionpair
dynamics and ionic conductivity, shows that increasing the water content of IL accelerates its dynamics. This
effect is noticeable at water mole fractions higher than ≈0.6.
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