Extraction of Cations from an Ionic Liquid Droplet in a Dielectric Liquid under Electric Field

Ionic
liquids show great promise as excellent solvents or catalysts
in energy and biological fields due to their unique chemical and physical
properties. In this work, the characteristics of various ionic liquids
are investigated with the electrophoresis of a charged droplet (ECD)
method. Under normal situation, a charged droplet in a dielectric
liquid shows back-and-forth bouncing motion between the positive and
negative electrodes continuously. However, for some special ionic
liquids, interesting retreating behavior of a charged droplet has
been observed. This retreating behavior is due to the loss of positive
charges of the droplet, and it suggests that only the positive ions
are extracted from the droplet under the applied electric field. Based
on this hypothesis of ion extraction, Fourier transform infrared (FTIR)
spectroscopy analysis has been performed. The retreating behavior
is also discussed from the intermolecular point of view according
to the ion species.