Electrowetting of ionic liquids.
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.
Millefiorini
Stefano
S
Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA 5095, Australia.
Tkaczyk
Alan H
AH
Sedev
Rossen
R
Efthimiadis
Jim
J
Ralston
John
J
D004563:Electrochemistry; D048288:Imidazolines / Q000737:chemistry*; D007477:Ions; D011759:Pyrrolidines / Q000737:chemistry*; D017155:Wettability
D048288:Imidazolines; D007477:Ions; D011759:Pyrrolidines