title: Direct force measurements between silica particles in aqueous solutions of ionic liquids containing 1-butyl-3-methylimidazolium (BMIM).
abstract: Direct force measurements between silica particles were carried out using the colloidal probe technique, which is based on an atomic force microscope (AFM). The forces were investigated in aqueous solutions of ionic liquids (ILs) containing 1-butyl-3-methylimidazolium (BMIM) cations and chloride, dicyanamide, and thiocyanate as anions up to concentrations of about 1 M. The results were compared with the simple electrolyte KCl. ILs behave similar to the simple electrolyte at low concentrations, as the ILs dissociate fully into ions, and they lead to repulsive double layer forces. At higher concentrations, attractive van der Waals forces set in, but they are enhanced in the presence of ILs by additional attractive force, whose strength depends on the type of IL. This additional attraction probably originates from the interaction of adsorbed IL layers.
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Geneva, Sciences II, 30 Quai Ernest-Ansermet, 1205 Geneva, Switzerland. michal.borkovec@unige.ch.
authors.forename: Valentina
authors.initials: V
authors.lastname: Valmacco
authors.forename: Gregor
authors.initials: G
authors.lastname: Trefalt
authors.forename: Plinio
authors.initials: P
authors.lastname: Maroni
authors.forename: Michal
authors.initials: M
authors.lastname: Borkovec