(754b) Long Range Electrostatic Screening in Ionic Liquids

As liquids composed solely of ions, the scientific consensus has been that ionic liquids have exceedingly high ionic strengths and very short Debye screening lengths. However, recent experiments from several independent laboratories reveal remarkable long range forces that appear to be electrostatic in origin. We discuss temperature-dependent surface force measurements that yield insight into the mechanism of these long range forces and propose a general model of long-range electrostatic screening in ionic liquids, where thermal fluctuations, either free dissociated ions or correlated domains, take on the role of ions in traditional dilute electrolyte solutions. More broadly, our work provides an alternative way of envisioning highly concentrated electrolytes, with implications for diverse areas of inquiry, ranging from designing electrochemical devices to rationalizing electrostatic interactions in biological systems.