2D or not 2D: Structural and charge ordering at the solid-liquid interface of the 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate ionic liquid

Abstract

Molecular dynamics simulations of a 5 nm-thick layer of the ionic liquid 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate, [(OH)C₂C₁im][BF₄], over silica, alumina and boro-silicate glass substrates have been performed. The structure of the ionic liquid at the solid-liquid interface has been interpreted taking into account the corresponding normal density profiles, lateral interfacial structure, orientational ordering and planar density contours. Comparisons with experimental data suggest that the adsorption and stratification process of ionic liquids over solid substrates can be correctly modeled using a realistic rendition of a non-uniform amorphous substrate such as a glass material.