title: Nanostructured solvation in mixtures of protic ionic liquids and long-chained alcohols.
abstract: The structural and dynamical properties of bulk mixtures of long-chained primary and secondary alcohols (propanol, butanol, and 2-pentanol) with protic ionic liquids (ethylammonium and butylammonium nitrate) were studied by means of molecular dynamics simulations and small angle X-ray scattering (SAXS). Changes in the structure with the alcohol concentration and with the alkyl chain length of the alcohol moieties were found, showing variations in the radial distribution function and in the number of hydrogen bonds in the bulk liquids. Moreover, the structural behaviour of the studied mixtures is further clarified with the spatial distribution functions. The global picture in the local scale is in good agreement with the nanostructured solvation paradigm [T. Méndez-Morales et al. Phys. Chem. B 118, 761 (2014)], according to which alcohols are accommodated into the hydrogen bonds' network of the ionic liquid instead of forming clusters in the bulk. Indeed, our study reveals that the alcohol molecules are placed with their polar heads at the interfaces between polar and nonpolar nanodomains in the ionic liquid, with their alkyl chains inside the nonpolar organic nanodomains. The influence of alcohol chain length in the single-particle dynamics of the mixtures is also reported calculating the velocity autocorrelation function and vibrational densities of states of the different species in the ionic liquid-alcohol mixtures, and a weak caging effect for the ethylammonium cations independent of the chain size of the alcohols was found. However, the SAXS data collected for the studied mixtures show an excess of the scattering intensities which indicates that there are also some structural heterogeneities at the nanoscale.
authors.affiliation: Grupo de Nanomateriais, Fotónica e Materia Branda, Departamentos de Física de Partículas e de Física Aplicada, Universidade de Santiago de Compostela, Campus Vida s/n, E-15782 Santiago de Compostela, Spain.
authors.forename: Hadrián
authors.identifier: 0000000198618076
authors.initials: H
authors.lastname: Montes-Campos
authors.affiliation: Grupo de Nanomateriais, Fotónica e Materia Branda, Departamentos de Física de Partículas e de Física Aplicada, Universidade de Santiago de Compostela, Campus Vida s/n, E-15782 Santiago de Compostela, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Otero-Mato
authors.affiliation: Grupo de Nanomateriais, Fotónica e Materia Branda, Departamentos de Física de Partículas e de Física Aplicada, Universidade de Santiago de Compostela, Campus Vida s/n, E-15782 Santiago de Compostela, Spain.
authors.forename: Trinidad
authors.initials: T
authors.lastname: Méndez-Morales
authors.affiliation: Grupo de Nanomateriais, Fotónica e Materia Branda, Departamentos de Física de Partículas e de Física Aplicada, Universidade de Santiago de Compostela, Campus Vida s/n, E-15782 Santiago de Compostela, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: López-Lago
authors.affiliation: Dipartimento di Chimica, Sapienza Università di Roma, Piazzale Aldo Moro 5, I-00185 Roma, Italy.
authors.forename: Olga
authors.initials: O
authors.lastname: Russina
authors.affiliation: Facultade de Ciencias, Universidade da Coruña, Campus A Zapateira s/n, E-15071 A Coruña, Spain.
authors.forename: Oscar
authors.identifier: 0000000262471161
authors.initials: O
authors.lastname: Cabeza
authors.affiliation: Grupo de Nanomateriais, Fotónica e Materia Branda, Departamentos de Física de Partículas e de Física Aplicada, Universidade de Santiago de Compostela, Campus Vida s/n, E-15782 Santiago de Compostela, Spain.
authors.forename: Luis J
authors.initials: LJ
authors.lastname: Gallego
authors.affiliation: Grupo de Nanomateriais, Fotónica e Materia Branda, Departamentos de Física de Partículas e de Física Aplicada, Universidade de Santiago de Compostela, Campus Vida s/n, E-15782 Santiago de Compostela, Spain.
authors.forename: Luis M
authors.initials: LM
authors.lastname: Varela