title: Influence of the anion on the electrical conductivity and glass formation of 1-butyl-3-methylimidazolium ionic liquids.
abstract: Six ionic liquids based on the 1-butyl-3-methylimidazolium cation have been studied. As anions Cl(-), Br(-), I(-), [NCS](-), [N(CN)(2)](-), and [BF(4)](-) were selected. The electrical conductivities were determined between 173 and 393 K based on impedance measurements in the frequency range from 0.1 to 10(7) Hz. The electrical conductivity increases, whereas the glass transition temperature, the fragility, and the low temperature activation energy decrease with increasing anion size. The results can be understood from the changing anion-cation interaction strength with changing anion size and from the energy landscape interpretation of the glass transition dynamics.
authors.affiliation: Laboratorium voor Akoestiek en Thermische Fysica, Departement Natuurkunde en Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200D, P.O. Box 2416, B-3001 Leuven, Belgium. jan.leys@fys.kuleuven.be
authors.forename: Jan
authors.initials: J
authors.lastname: Leys
authors.forename: Ravindran Nair
authors.initials: RN
authors.lastname: Rajesh
authors.forename: Preethy Chirukandath
authors.initials: PC
authors.lastname: Menon
authors.forename: Christ
authors.initials: C
authors.lastname: Glorieux
authors.forename: Stéphane
authors.initials: S
authors.lastname: Longuemart
authors.forename: Peter
authors.initials: P
authors.lastname: Nockemann
authors.forename: Michael
authors.initials: M
authors.lastname: Pellens
authors.forename: Koen
authors.initials: K
authors.lastname: Binnemans