Electrokinetic Transport in Room-Temperature Ionic Liquids: Amplification by Short-Wavelength Hydrodynamics

Electrokinetic transport in room-temperature ionic liquids (RTILs) plays an important role in their applications but is only begun to be understood. Here we report on the atomistic simulation of electroosmotic flows (EOF) in RTILs. We find that, although the EOF is suppressed by the ion-wall electrofriction, its strength greatly exceeds that predicted by classical hydrodynamic theories if correct ion distribution is used and electrofriction effects are effectively accounted for in these theories. We trace the unexpected flow strength to the short-wavelength nature of EOF in RTILs. We show that the EOF in RTILs is a rare example in which short-wavelength hydrodynamics profoundly affects flow measurables in macroscopic systems and thus is a good test bed for developing improved theories for generalized hydrodynamics.