Molecular dynamics simulation of the behaviour of water in nano-confined ionic liquid-water mixtures.

This work describes the behaviour of water molecules in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid under nanoconfinement, between graphene sheets. By means of molecular dynamics simulations, the adsorption of water molecules at the graphene surface is studied. A depletion of water molecules in the vicinity of the neutral and negatively charged graphene surfaces, and their adsorption at the positively charged surface are observed in line with the preferential hydration of the ionic liquid anions. The findings are appropriately described using a two-level statistical model. The confinement effect on the structure and dynamics of the mixtures is thoroughly analyzed using the density and the potential of mean force profiles, as well as by the vibrational densities of the states of water molecules near the graphene surface. The orientation of water molecules and the water-induced structural transitions in the layer closest to the graphene surface are also discussed.We acknowledge the supercomputing support from the EPSRC funded ARCHIE-WeSt HighPerformance Computer centre (www.archie-west.ac.uk, EPSRC grant no. EP/K000586/1) and the Galician Supercomputing Centre (CESGA). The financial support of the Estonian Materials Technology Program Project SLOKT12180T, Project of European Structure Funds SLOKT12026T, Estonian Institutional Research Project IUT20-013, Estonian Personal Research Project PUT1107, and Estonian Centres of Excellence in Science Project: High-technology Materials for Sustainable Development TK117 is highly appreciated. The financial support of the Spanish Ministry of Economy and Competitiveness MAT2014-57943-C3-1-P and MAT2014- 57943-C3-3-P is gratefully acknowledged. Moreover, this work was funded by the Spanish Ministry of Economy and Competitiveness (FIS2012-33126) and by the Xunta de Galicia (AGRUP2015/11). All these research projects were partially supported by FEDER. Funding from the European Union (COST Action CM 1206) and by the Galician Network on Ionic Liquids, REGALIs (CN 2014/015) is also acknowledged

Molecular dynamics simulation of the structure and interfacial free energy barriers of mixtures of ionic liquids and divalent salts near a graphene wall

A molecular dynamics study of graphene-confined mixtures of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4]) with Mg[BF4]2 is reported.</p