The synthesis and characterization of six new ionic liquids, with fluoroether moeties on the imidazolium ring, each with vapor pressures shown to be <10–7 Torr at 25 °C, have been demonstrated. Thermal stability of the ionic liquids up to 250 °C was demonstrated. The ionic liquids had no measurable influence upon viscosity upon addition to perfluoropolyether (PFPE) base fluids. They also had no measureable influence upon corrosion on steel substrates upon addition to base fluids. In general, 13 to 34% lower COFs (coefficients of friction), and 30 to 80% higher OK load of base fluids upon addition of the ionic liquids was shown.
The compound consists of a 1,3-disubstituted imidazolium cation. The substituents comprise perfluoroether groups. A bis(trifluoromethanesulfonyl) imide anion counterbalances the charge. The fluorinated groups are intended to enhance dispersion of the ionic liquid in the PFPE base fluid. The presence of weak Van der Waals forces associated with fluorine atoms will limit interaction of the substituents on adjacent ions. The longer interionic distances will reduce the heat of melting and viscosity, and will increase dispersion capabilities.
This work was done by Bryan Bergeron, David Skyler, Kyle Roberts, and Amy Stevens of Physical Sciences, Inc. for Glenn Research Center.
Inquiries concerning rights for the commercial use of this invention should be addressed to NASA Glenn Research Center, Innovative Partnerships Office, Attn: Steven Fedor, Mail Stop 4–8, 21000 Brookpark Road, Cleveland, Ohio 44135. LEW-19039-1