title: Electrowetting of ionic liquids.
abstract: We have successfully demonstrated that imidazolium- and pyrrolidinium-based commercial room-temperature ionic liquids can electrowet (with a dc voltage) a smooth fluoropolymer (Teflon AF1600) surface. Qualitatively, the process is analogous to the electrowetting of aqueous electrolyte solutions: the contact angle versus voltage curve has a parabolic shape which saturates at larger voltages (positive or negative). On the other hand we observed several peculiarities: (i) the efficiency is significantly lower (by about an order of magnitude); (ii) the influence of the bulky cation is larger and the importance of the smaller anion is lesser, especially with respect to electrowetting saturation; (iii) there is an asymmetry in the saturation contact angles found for positive and negative voltages. The asymmetry may be correlated with the cation-anion asymmetry of the ionic liquids. The low efficiency may be caused by the presence of water and other impurities in these commercial materials.
authors.affiliation: Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA 5095, Australia.
authors.forename: Stefano
authors.initials: S
authors.lastname: Millefiorini
authors.forename: Alan H
authors.initials: AH
authors.lastname: Tkaczyk
authors.forename: Rossen
authors.initials: R
authors.lastname: Sedev
authors.forename: Jim
authors.initials: J
authors.lastname: Efthimiadis
authors.forename: John
authors.initials: J
authors.lastname: Ralston
mesh_terms: D004563:Electrochemistry; D048288:Imidazolines / Q000737:chemistry*; D007477:Ions; D011759:Pyrrolidines / Q000737:chemistry*; D017155:Wettability
chemical_list: D048288:Imidazolines; D007477:Ions; D011759:Pyrrolidines