Complementary Molecular Dynamics and X-ray Reflectivity Study of an Imidazolium-Based Ionic Liquid at a Neutral Sapphire Interface.
Understanding the molecular-level behavior of ionic liquids (ILs) at IL-solid interfaces is of fundamental importance with respect to their application in, for example, electrochemical systems and electronic devices. Using a model system, consisting of an imidazolium-based IL ([C2Mim][NTf2]) in contact with a sapphire substrate, we have approached this problem using a complementary combination of high-resolution X-ray reflectivity measurements and atomistic molecular dynamics (MD) simulations. Our strategy enabled us to compare experimental and theoretically calculated reflectivities in a direct manner, thereby critically assessing the applicability of several force-field variants. On the other hand, using the best-matching MD description, we are able to describe the nature of the model IL-solid interface in appreciable detail. More specifically, we find that characteristic interactions between the surface hydroxyl groups and donor and acceptor sites on the IL constituents have a dominant role in inducing a multidimensional layering profile of the cations and anions.
†Institute for Theoretical Physics, FAU Erlangen-Nürnberg, Staudtstrasse 7, 91058 Erlangen, Germany.
Zlatko
Z
Brkljača
‡Crystallography and Structural Physics, FAU Erlangen-Nürnberg, Staudtstrasse 3, 91058 Erlangen, Germany.
Michael
M
Klimczak
†Institute for Theoretical Physics, FAU Erlangen-Nürnberg, Staudtstrasse 7, 91058 Erlangen, Germany.
Zoran
Z
Miličević
‡Crystallography and Structural Physics, FAU Erlangen-Nürnberg, Staudtstrasse 3, 91058 Erlangen, Germany.
Matthias
M
Weisser
§Chemical Reaction Engineering, FAU Erlangen-Nürnberg, Egerlandstrasse 3, 91058 Erlangen, Germany.
Nicola
N
Taccardi
§Chemical Reaction Engineering, FAU Erlangen-Nürnberg, Egerlandstrasse 3, 91058 Erlangen, Germany.
Peter
P
Wasserscheid
⊥Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia.|∥Center for Computational Chemistry, FAU Erlangen-Nürnberg, Nägelsbachstrasse 25, 91052 Erlangen, Germany.
David M
DM
Smith
‡Crystallography and Structural Physics, FAU Erlangen-Nürnberg, Staudtstrasse 3, 91058 Erlangen, Germany.
Andreas
A
Magerl
†Institute for Theoretical Physics, FAU Erlangen-Nürnberg, Staudtstrasse 7, 91058 Erlangen, Germany.|⊥Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia.
Ana-Sunčana
AS
Smith
IL−solid interface; atomistic molecular dynamics; double layer; liquid ordering; surface characterization