title: Influence of electric potential on the apparent viscosity of an ionic liquid: facts and artifacts.
abstract: According to recent findings, the steady shear viscosity of the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim][Tf2N]) decreases significantly under the influence of electric potential. This implies a causal connection between nanoscale ordering at the electrified interface and a macroscopic change of transport properties. To study this phenomenon in more detail, we reproduced the above-mentioned measurements; however, we find no evidence that the viscosity of [Emim][Tf2N] is a function of electric potential. Additionally, our results show that steady shear measurements can lead to artifacts that, at first glance, may appear to be potential-induced changes in viscosity. We demonstrate that the artifacts result from a sliding electrical contact at the working electrode of the electrochemical cell and we suggest to consider our findings for future viscosity measurements of ionic liquids.
authors.affiliation: System and Component Design, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
authors.forename: Moritz A
authors.initials: MA
authors.lastname: Ploss
authors.affiliation: Surface and Corrosion Science, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden. mark@kth.se and Chemistry, Materials and Surfaces, Box 5607, SE-114 86 Stockholm, Sweden.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Rutland
authors.affiliation: System and Component Design, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden and Mechanical Construction and Production, Ghent University, B-9000 Ghent, Belgium.
authors.forename: Sergei
authors.initials: S
authors.lastname: Glavatskih