Ionic liquids at the air/water interface

► We present MD experiments of two ionic liquids adsorbed at air/water interfaces. ► We examine a wide range of surface concentration of [C8mim][I] and [C8mim][Cl]. ► The systems exhibited marked structural differences at the interface. ► These discrepancies are due to the different surface behavior of the anionic species. ► We provide arguments for the interpretation of surface tension experimental results.