pi-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 pi-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.

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Ionic liquids have become an increasingly popular class of solvent in the last decade as the potential applications of these materials become more diverse. Rather than being viewed simply as replacement for conventional organic solvent media, research into ionic liquids has progressed to the deliberate choice and design of these materials for reasons of improved rate, specificity, and yield. Design of ionic liquids centres on the development of novel cations and anions to impart the specific physical properties required for each application. Therefore, the materials being synthesized and studied are also becoming increasingly complex and diverse. Here we provide an overview of ionic liquids generally, and some of their current applications, as well as an introduction to some of the new cations and anions that have been developed for specific properties.

New families of salts, based on quaternary ammonium, 1-methyl-3-alkylimidazolium or N-methyl-N-alkylpyrrolidinium organic cations together with the dicyanamide (dca, N(CN) 2 2 ) anion are reported. The salts are low melting compounds, all those reported are liquid at room temperature, for example 1-methyl-3-ethylimidazolium dicyanamide (mp 221 °C) and N-methyl-N-ethylpyrrolidinium dicyanamide (mp 210 °C). Some of the salts exhibit multiple crystalline phases below their melting points. Above their melting points they are stable to at least 200 °C. Many of the salts were found to be glass forming when cooled rapidly to 2100 °C. The room-temperature liquids exhibit very low viscosities, for example ethylmethylimidazolium dicyanamide: h = 21 cP at ambient temperature (25 °C).

Ionic liquids which are (weak) Lewis bases have a number of interesting and useful properties different to those of traditional ionic liquids, including volatility and the possibility of being distillable in some cases, a base catalysis effect in others and enhancement of the acidity of dissolved acids.