Room temperature ionic liquids viscosity

The temperature dependence of viscosity of 23 room-temperature ionic liquids was investigated. The size and symmetry of the cations and anions were shown to have a marked effect on viscosity (79). 

Noda, A., Hayamizu, K., and Watanabe, M., Pulsed-gradient spin-echo H and NMR ionic diffusion coefficient, viscosity and ionic conductivity of non-chloroaluminate room-temperature ionic liquids, /. Phys. Chem. B, 105, 4603,2001. 

Okoturo, 0.0. and Van der Noot, T.J., Temperature dependence of viscosity for room temperature ionic liquids, ]. Electroanal. Chem., 568,167, 2004. 

In fact, the majority of functionalized onium salts are solids, very viscous or waxy at room temperature, which makes them difficult to use as such. This is even truer for salts bearing complex substituents. Since non-functional room temperature ionic liquids can usually easily dissolve other salts, they can be used as solvents to make low viscosity solutions of high melting point TSOSs, resulting in mixtures... 

Sanmamed YA, Gonzdlez-Salgado D, Troncoso J et al. (2007) Viscosity-induced errors in the density determination of room temperature ionic liquids using vibrating tube densitometry. Fluid Phase Equilib 252 96-102... 

Widegren JA, Laesecke A, Magee JW (2005) The effect of dissolved water on the viscosities of hydrophobic room-temperature ionic liquids. Chem Commun 12 1610-1612... 

Table 3.2-3 Viscosity and density data for other room-temperature ionic liquids... 

FIGURE 2.70 Cyclic voltammograms for [EMIMllBFJ at 5 mV s" . (Sillars, F. B. et al. 2012. Variation of electrochemical capacitor performance with room temperature ionic liquid electrolyte viscosity and ion size. Physical Chemistry Chemical Physics 14 6094-6100. Reproduced by permission of The Royal Society of Chemistry.)... 

Some typical room temperature ionic liquids and their physical properties are summarized in Table 2. The viscosity of most ionic liquids is substantially greater than traditional solvents. Elevated temperatures or dilution with conventional solvents of high dielectric constant can be used to lower the viscosity into a more desirable range. High viscosity, variable purity, and interference in absorbance detection at low wavelengths are the primary problems for the wider use of ionic liquids in electrophoresis at present. On the other hand, new ionic liquids are introduced at frequent intervals, and knowledge is... 

Carbonate-containing liquid electrolytes are primarily chosen for their ability to dissolve lithium salts and their relatively low viscosity (which facilitates Li-ion diffusion between electrodes). Their flammability has in part led to interest in the use of room-temperature ionic liquids (ILs) as replacements. ILs can potentially operate in a higher voltage window relative to carbonates and also have the added benefit of being more thermally stable and having low vapor pressure. The main drawback of this class of compounds is a high viscosity. Additionally, carbonates may have to be introduced at certain voltages to form a suitable SEI for operation. 

Lovelock KRJ, Cowling FN, Taylor AW, Licence P, Walsh DA (2010) Effect of viscosity on steady-state voltammetry and scanning electrochemical microscopy in room temperature ionic liquids. J Phys Chem B 114 4442-4450... 

Margulis, C.J., Room-temperature ionic liquids Slow dynamics, viscosity, and the red edge effect, Acc. Chem. Res. 40,1097-1105 (2007). 

Most of the 1,2,3-triazolium based ionic liquids are room temperature ionic liquids (RTILs) (Fletcher, Keeney et al. 2010 Khan, Hanelt et al. 2009). So far, not so many physical constants have been reported. Viscosity measurements and differential thermogravimetry (TGA) measurements of some 1,3,4-trisubstituted 1,2,3-triazolium ionic liquids counter-ions Qeong and Ryu 2010 Khan, Hanelt et al. 2009). These reports indicated good thermal stability up to 355 °C, which is strongly dependent on several variables such as the kind of counter-ion and the nature of substituents on the triazolium ring. One can tune the stability of 1,2,3-... 

Seki, S., Hayamizu, K, Tsuzaki, S., Fujii, K, Umebayashi, Y., Mitsugi, T., Kobayashi, T., Ohno, Y., Kobayashi, Y., Mita, Y., Miyashiro, H., Ishiguro, S. (2009) Relationship between Center Atom Sp>ecies (N, P) and Ionic Conductivity, Viscosity, Density, Self-diffusion Coefficient of Quaternary Cation Room-Temperature Ionic Liquids, Phys. Chem. Chem. Phys. VoL 11 3509-3514. 

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