Viscosity of electrolytes

Stokes, R. H. Mills, R. "Viscosity of Electrolytes and Related Properties" in "The International Encyclopedia of Physical Chemistry and Chemical Physics Topic 16, Transport Properties of Electrolytes" Vol. 3, Stokes, R. H., Ed., Pergamon Press, Oxford, 1965. 

C. Concentration Dependence of Ionic Mobility and Viscosity of Electrolyte Solutions... 

The calculation of viscosities of electrolyte mixtures can be accomplished with the method of Andrade (see Ref. [40]) extended with the electrolyte correction by Jones-Dole [44]. First, the pure component viscosities of molecular species are determined by the three-parametric Andrade equation, which allows a mixing rule to be applied and the mixture viscosity of an electrolyte-free liquid phase to be obtained. The latter is transformed into the viscosity of the liquid phase using the electrolyte correction term of Jones and Dole [44], whereas the ionic mobility and conductivity are used as model parameters. 

Jones-Dole equation, coefficients (viscosity of electrolytes) 1.5.52, table 1.5.9, I.6.78ff... 

Concentration dependence of the viscosity of electrolyte solution has been empirically expressed by the Jones-Dole equation (eq.(l)),where r/ and rjo are the viscosities of solution 77/rjo = 1+aVc+Be (1)... 

Viscosities of Electrolyte Solutions A very large amount of work has been done on the viscosity of electrolyte solutions, much of it being related to the. electrical conductivity.1 Herz2 found that plotted against the specific volumes of aqueous salt solutions gave... 

Confirmation of this classihcation comes from studies on the partial molar volumes of ions, and from the compressibility and viscosity of electrolyte solutions and from the activation parameters for water exchange found from NMR and ultrasonic methods. 

However, dopant solubility and pH level must be considered, as these are also dependant on the choice of solvent. As mentioned previously, conventional sodium sulfonate dopants and anionic biomolecules are easily dissolved in water. Aqueous sodium sulfonate electrolytes have a pH range (pH 7-9) close to the body pH level and this would help to minimize pH-induced cytotoxicity when implanted in the body. Temperature can affect the solubility of dopant and even the viscosity of electrolyte. Generally, low temperature helps to produce smoother, more conductive films, but the reduced dopant solubility and the increased viscosity can be problematic [62]. 

While the viscosity of electrolytic solutions is not a thermodynamic property, such data frequently are reported with partial molal volumes, and viscosities are often valuable in elucidating the structure of solutions. Therefore, a few viscosity data which have a direct bearing on the discussion of the nature of these solutions are included. 

The same questions which arise in the division of enthalpies and free energies of solvation and transfer into their ionic components also arise in the division of entropies, volumes, and viscosities of electrolytes into their ionic components. However, because of the inherently simpler concepts involved, a greater variety of approaches in making the divisions have been employed. Some of these methods can also be used, as discussed in sect. 2.12.3, to estimate thermodynamic properties of electrolytes in organic solutions for which no data exist. 

Stokes, R.H. and Mills, R. (1965) Viscosity of Electrolytes, Pergamon, Oxford. 

Duca KA, Jordan PC (1997) Ion-water and water-water interactions in a gramicidinlike channel effects due to group polarizability and backbone flexibility. Biophys Chem 65 123-141 Falkenhagen H, Dole M (1929) Viscosity of electrolyte solutions and its significance to the Debye theory. Phys Z 30 611-622... 

Marcus Y (2005a) BET nodehng of solid-liquid phase diagrams of common ion binary stilt hydrate mixtures. 1. The BET parameters. J Sol Chem 34 297-306 Marcus Y (2006) On the molar volumes and viscosities of electrolytes. J Sol Chem 35 1271-1286 Marcus Y (2007) Gibbs energies of transfer of anions from water to mixed aqueous organic solvents. Chem Rev 107 3880-3897... 

Fatmi MQ, Hofer TS, Randolf BR, Rode BM (2005) An extended ab initio QM/MM MD approach to structure and dynamics of Zn(II) in aqueous solution. J Chem Phys 123 054514-1-8 Feakins D, Freemantle DJ, Lawrence KG (1974) Transition state treatment of the relative viscosity of electrolytic solutions, applications to aqueous, nonaqueous, and methanol + water systems. J Chem Soc Faraday Trans 70 795—806... 

Ibuki K, Nakahara M (1986) Dielectric friction theory of the viscosity of electrolyte solutions. J Chem Phys 85 7312-7317... 

Jiang J, Sandler S (2003) A New Model for the Viscosity of Electrolyte Solutions. Ind Eng Chem... 

St 65 Stokes, R. H., Mills, R. Viscosity of Electrolytes and Related Properties. Pergamon Press, New York 1965. 

The thermal conductivity and the viscosity of electrolyte solutions are also of research interest because of the long-range electrostatic interactions and the Coulombic forces between ions. 

The viscosity of electrolyte solutions is also of research interest because of the long-range electrostatic interactions (Coulombic forces) between ions (Harrap and Heymaim, 1951 Stokes and Mills, 1965 Home, 1972 Horvath, 1985 Chandra and Bagchi, 2000a,b Esteves etal, 2001 Anderko et al, 2002 Jiang and Sandler, 2003). 

The concentration dependence of the viscosity of electrolyte solutions is quite anomalous (Chandra and Bagchi, 2000a,b), and clearly depends upon the nature of the solute ions. For some electrolyte solutions (see Figures 6.10a,b), such as H2O + CsF, H2O + KF, H2O + LiCl, H2O + LiBr, H2O + Lil, H2O + NaCl, H2O + NaF and H2O + RbF and the viscosity increases monotonically with the electrolyte concentration, while for other types of electrolyte solutions such as H2O + CsCl, H2O -H KBr, H2O -H KCl, H2O + KI and H2O + RbCl the viscosity decreases at low electrolyte concentrations, reaching a minimum value, and then increases at higher concentrations. Hence, the modeling of the electrolyte-solutions viscosity over the whole concentration range is rather difficult. 

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