title: Charge-Induced Long-Range Order in a Room-Temperature Ionic Liquid.
abstract: We report direct evidence for charge-induced long-range (ca. 100 μm) order in the room-temperature ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM(+)BF4(-)), supported on a silica surface. We have measured the rotational diffusion dynamics of anionic, cationic, and neutral chromophores as a function of distance from a silica surface. The results reflect the excess charge density gradient induced in the IL by the (negative) charge present on the silica surface. Identical measurements in ethylene glycol reveal spatially invariant reorientation dynamics for all chromophores. Capping the silica support with Me2SiCl2 results in spatially invariant reorientation dynamics in the IL. We understand these data in the context of the IL exhibiting a spatially damped piezoelectric response mediated by IL fluidity and disorder.
authors: Department of Chemistry, Michigan State University , 578 South Shaw Lane, East Lansing, Michigan 48824, United States.
authors: Ke
authors: K
authors: Ma
authors: Department of Chemistry, Michigan State University , 578 South Shaw Lane, East Lansing, Michigan 48824, United States.
authors: Romana
authors: R
authors: Jarosova
authors: Department of Chemistry, Michigan State University , 578 South Shaw Lane, East Lansing, Michigan 48824, United States.
authors: Greg M
authors: GM
authors: Swain
authors: Department of Chemistry, Michigan State University , 578 South Shaw Lane, East Lansing, Michigan 48824, United States.
authors: Gary J
authors: GJ
authors: Blanchard
mesh_terms: D005454:Fluorescence Polarization; D052578:Ionic Liquids / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry; D013696:Temperature
chemical_list: D052578:Ionic Liquids; D012822:Silicon Dioxide