Submitted on April 8, 2002
Accepted on June 20, 2002
Use of Ionic Liquids for 
-Conjugated Polymer Electrochemical Devices
Wen Lu 1,
Andrei G. Fadeev 1,
Baohua Qi 1,
Elisabeth Smela 1,
Benjamin R. Mattes 1*,
Jie Ding 2,
Geoffrey M. Spinks 2,
Jakub Mazurkiewicz 2,
Dezhi Zhou 2,
Gordon G. Wallace 2,
Douglas R. MacFarlane 3,
Stewart A. Forsyth 3,
Maria Forsyth 3
1 Santa Fe Science and Technology (SFST), 3216 Richards Lane, Santa Fe, NM 87507, USA.
2 Intelligent Polymer Research Institute (IPRI), University of Wollongong, NSW, Australia.
3 Monash University, Department of Chemistry, Victoria, Australia.
* To whom correspondence should be addressed. E-mail: mattes{at}sfst.net.
Conjugated polymers that are electrochemically cycled in ionic liquids have enhanced lifetimes without failure (up to 1 million cycles) and fast cycle switching speeds (100 ms). We report results for electrochemical mechanical actuators, electrochromic windows, and numeric displays made from three types of -conjugated polymers: polyaniline, polypyrrole, and polythiophene. Experiments were performed under ambient conditions, yet the polymers showed negligible loss in electroactivity. These performance advantages were obtained by using environmentally stable, room-temperature ionic liquids composed of 1-butyl-3-methyl imidazolium cations together with anions such as tetrafluoroborate or hexafluorophosphate.
