The ecotoxicity and tribological properties of choline amino acid ionic liquid lubricants

This research into environmentally-friendly ionic liquids (ILs) used a series of choline amino acid ILs ([Ch][AA] ILs) prepared from choline cations and several amino acid anions. Their physicochemical and tribological properties were tested, and the results showed that [Ch][AA] ILs had good lubricating properties for different friction pairs at room temperature (RT). Their toxicities were checked against three aquatic organisms: brine shrimp, zebrafish and green algae. The results showed that they have a remarkably low toxicity. Versus traditional IL 1-butyl-3-methyl imidazolium tetrafluoroborate (L-B104), the [Ch][AA] ILs had comparable or even better physicochemical and tribological properties. More importantly, they had the environmentally features of biodegradability and non-toxicity.