(376bd) Wetting Behavior of Imidazolium Based Ionic Liquids: A Molecular Dynamics Study

Aqueous ionic liquids due to unique properties ^1,2 are of special interest, in-depth understanding of the structure–property relation of the systems is therefore desirable. Molecular dynamics (MD) simulations are performed to investigate the wetting behavior of aqueous imidazolium based ionic liquids (ILs), consist of the 1-ethyl-3-methylimidazolium ([EMIM]) cation combined with hydrophilic boron tetrafluoride ([BF4]) and hydrophobic bis (trifluoromethylsulfonyl)imide ([NTf2]) anion. To understand the influence of anion on solid-liquid interface of graphite surface together with varying the IL concentrations between 0 to 30 wt % are studied. The wetting behavior of both the IL droplets is characterized through a density profile, and orientation order paramete. The contact angle of aqueous IL decreases with increasing the ion-pair of IL in water. Due to the preferred adsorption of ILs, water starts to deplete from the surface with an increase in the ionic liquid concentration. Hydrophobic nature of ([NTf2]) anion drags the liquid towards the interface from the bulk. The nature of water-anion hydrogen bond networks, nature of anions, interaction with the surface are the determining factors in the wetting behavior of the aqueous ionic liquids

References:

(1) Bhargava, B. L.; Klein, M. L. Aqueous Solutions of Imidazolium Ionic Liquids: Molecular Dynamics Studies. Soft Matter 2009, 5 (18), 3475–3480.

(2) Oprzeska-Zingrebe, E. A.; Smiatek, J. Aqueous Ionic Liquids in Comparison with Standard Co-Solutes : Differences and Common Principles in Their Interaction with Protein and DNA Structures. Biophysical reviews 2018, 10 (3), 809–824.