title: Aqueous Solutions of Ionic Liquids: Microscopic Assembly.
abstract: Aqueous solutions of ionic liquids are of special interest, due to the distinctive properties of ionic liquids, in particular, their amphiphilic character. A better understanding of the structure-property relationships of such systems is hence desirable. One of the crucial molecular-level interactions that influences the macroscopic behavior is hydrogen bonding. In this work, we conduct molecular dynamics simulations to investigate the effects of ionic liquids on the hydrogen-bond network of water in dilute aqueous solutions of ionic liquids with various combinations of cations and anions. Calculations are performed for imidazolium-based cations with alkyl chains of different lengths and for a variety of anions, namely, [Br](-), [NO3](-), [SCN](-) [BF4](-), [PF6](-), and [Tf2N](-). The structure of water and the water-ionic liquid interactions involved in the formation of a heterogeneous network are analyzed by using radial distribution functions and hydrogen-bond statistics. To this end, we employ the geometric criterion of the hydrogen-bond definition and it is shown that the structure of water is sensitive to the amount of ionic liquid and to the anion type. In particular, [SCN](-) and [Tf2N](-) were found to be the most hydrophilic and hydrophobic anions, respectively. Conversely, the cation chain length did not influence the results.
authors.affiliation: Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, Ctra. Utrera km 1., 41013, Seville, Spain.
authors.forename: Jose Manuel
authors.identifier: http://orcid.org/0000-0001-8712-5591
authors.initials: JM
authors.lastname: Vicent-Luna
authors.affiliation: Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
authors.forename: David
authors.identifier: http://orcid.org/0000-0002-4382-1509
authors.initials: D
authors.lastname: Dubbeldam
authors.affiliation: Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, Ctra. Utrera km 1., 41013, Seville, Spain. pgomalv1@upo.es.
authors.forename: Paula
authors.identifier: http://orcid.org/0000-0001-9440-0600
authors.initials: P
authors.lastname: Gómez-Álvarez
authors.affiliation: Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, Ctra. Utrera km 1., 41013, Seville, Spain. scalero@upo.es.
authors.forename: Sofia
authors.identifier: http://orcid.org/0000-0001-9535-057X
authors.initials: S
authors.lastname: Calero
keywords: hydrogen bonds; imidazolium; ionic liquids; molecular dynamics; structure of water