title: Microrheological investigations in ionic liquids using optical trapping techniques.
abstract: In this paper, we demonstrate optical trapping of melamine particles (d ≈ 2.3 μm) within the pure ionic liquid ethylammonium nitrate (EAN) and show the first microrheological investigations of these important compounds using this technique. By analyzing the power spectrum of a particle trapped in EAN, we monitor the variation in viscous drag that it experiences in proximity to the sample coverslip, showing excellent agreement with Faxén's law. We also demonstrate hydrodynamic coupling between pairs of trapped particles. Finally, we explore temperature-dependent viscosity changes in ∼μL samples of EAN as a further example of microrheological investigations of ILs.
authors.affiliation: Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford , South Parks Road, Oxford OX1 3QZ, United Kingdom.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Dear
authors.forename: Emma K
authors.initials: EK
authors.lastname: Worrall
authors.forename: William D
authors.initials: WD
authors.lastname: Gault
authors.forename: Grant A D
authors.initials: GA
authors.lastname: Ritchie