Intrinsic Structure of the Interface of Partially Miscible Fluids: An Application to Ionic Liquids

Autor(en)

Gyoergy Hantal, Marcello Sega, Sofia Kantorovich, Christian Schroeder, Miguel Jorge

Abstrakt

We investigate by means of Molecular Dynamics simulations how the intrinsic surface structure of liquid/liquid interfaces involving ionic liquids depends on the opposite phase of varying polarity. We study 1-n-butyl-3-methylimidazolium hexafluorophosphate (BMIM PF

₆) and 1-n-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imid (BMIM NTf

₂). The opposite phase is either cyclohexane or water, but as a reference, IL-vacuum interfaces are also studied. We combine a distance-based cluster search algorithm with the ITIM intrinsic analyzing method to separate liquid phases showing non-negligible mutual miscibility and to identify atoms residing at the instantaneous surface. In contrast to the well structured surface of IL-vacuum systems, at liquid/liquid interfaces of ILs density correlations, ionic associations, and orientational preferences are all weakened, this effect being much more pronounced when the other species is water. In such systems we observe a drastic reduction in the presence of the cation at the surface and an increase of appearance of polar moieties (of both the cations and anions) leading to decreased apolar character of the interface. Furthermore, cations are mostly found to turn with their butyl chains toward the bulk while having their methyl groups sticking toward water. Anion-cation associations are reduced and partially replaced by water-anion and rarely also water-cation associations.

Organisation(en)

Institut für Computergestützte Biologische Chemie, Computergestützte Physik und Physik der Weichen Materie

Externe Organisation(en)

Eszterházy Károly University of Applied Sciences, Ural Federal University, University of Strathclyde

Journal

The Journal of Physical Chemistry Part C (Nanomaterials and Interfaces)

Band

119

Seiten

28448-28461

Anzahl der Seiten

14

ISSN

1932-7447

DOI

https://doi.org/10.1021/acs.jpcc.5b09810

Publikationsdatum

12-2015

Peer-reviewed

Ja

ÖFOS 2012

104017 Physikalische Chemie, 103006 Chemische Physik

Schlagwörter

ASJC Scopus Sachgebiete

Electronic, Optical and Magnetic Materials, Allgemeine Energie, Surfaces, Coatings and Films, Physical and Theoretical Chemistry

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/d7cd2aa4-65dd-4bc4-bed4-82f3d4b74d2c