Electrowetting of ionic liquids

J Am Chem Soc. 2006 Mar 8;128(9):3098-101. doi: 10.1021/ja057606d.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Electrochemistry
  • Imidazolines / chemistry*
  • Ions
  • Pyrrolidines / chemistry*
  • Wettability

Substances

  • Imidazolines
  • Ions
  • Pyrrolidines