The evidence for surface crystallization in ionic liquids is scarce. The existing reports seem to be contradictory
as for its driving forces, since in the two compounds investigated in the literature, the
contribution of coloumbic and van der Waals forces is very different. In this work 1-dodecyl-3-
methylimidazolium tetrafluoroborate was studied and its surface crystallization characterized by surface
tension, ellipsometry and optical microscopy. The results obtained seem to reconcile previous
observations, and it was further shown, using the same techniques, that this phenomenon is prevalent in
other ionic liquids. MD simulation results illustrate the different possibilities of organization, providing
reasonable models to rationalize the experimental observations.
