Figure 2.

Ionic structures (left) corresponding to ILs for which the viscosities at 25 °C (calculated from VTF fits) vs chain length are plotted on the right. Colors on the left match those of the symbols on the right. Alkylimidazolium NTf₂^– viscosities are from Tariq et al.²⁴ Alkylpyrrolidinium NTf₂^– viscosities for n = 3, 6, and 10 are from Jin et al.,²⁵ the one for n = 4 is from Funston et al.,²⁶ and those for n = 5, 7, and 8 are from Lall-Ramnarine et al.²⁷ Ether imidazolium and pyrrolidinium NTf₂^– viscosities with an ethylene bridge for n = 7 and 10, as well as for n = 4 for imidazolium, are from Lall-Ramnarine et al.²⁷ while n = 4 for pyrrolidinium is from Funston et al.²⁸ Ether imidazolium and pyrrolidinium NTf₂^– viscosities with a methylene bridge are from Chen et al.²⁹