Local Structure and Flow Properties of Ionic Liquids on Charged and Inert Substrates

We extract the conservative and dissipative interactions of the ionic liquid [Emim]+[NTf2]− on mica and HOPG. Charge-mediated layering on mica locks the counterions strongly in place, resulting in several liquid layers forming as the wall effect is integrated out, as well as much greater damping between the layers as compared to the bulk. Template-mediated layering on HOPG is much weaker than its Coulombic counterpart. In terms of local flow properties, layers on HOPG can glide easier over each other as compared to the bulk. This clearly demonstrates the importance of substrate for controlling near-wall dynamic response.