Relative Viscosity Data Research Articles

The viscosity of microemulsions

Microemulsions have been prepared from benzene and water using emulsifier blends of 5% Tween 20 + 1% Span 20 or 10% Tween 20 + 1% Span 20. The volume concentration of the dispersed phase (ϕ) extended up to 0.406, and the mean particle diameter ranged from 543A–1245A. The steady-state viscosities of these microemulsions, as determined in a capillary viscometer, could not be represented by any equation which merely related viscosity and dispersed phase volume concentration. After allowing for the volume ( ϕ 8) of benzene solubilized within the micelles of excess emulsifier, the relative viscosity ( n rel ) data conformed to Nrel= exp a(δ−δ s) 1−k(δ−δ s where k is a hydrodynamic interaction coefficient which depends empirically on mean particle size ( D m ) according to k = 1.079 + exp( 0.01008 D m ) + exp ( 0.00290 D m 2 . has a higher value (1.95–2.08) than predicted by Taylor's theory, although it is well below the value of 2.5 for solid spheres. Several factors may hinder fluid circulation within the droplets.

Osmotic coefficients, density, and relative viscosity data for aqueous solutions of thiourea at 25°

Osmotic coefficients, density, and relative viscosity data for aqueous solutions of thiourea at 25°

Frictional coefficients of aqueous solutions of choline chloride at 25°

Frictional coefficients for the binary system H2O–choline chloride have been calculated from experimentally determined diffusion coefficients, densities, and activity coefficients, and cover the concentration range 0·1 moles dm.–3 to 1·6 moles dm.–3 Using a modified form of Agar's equation which utilises diffusion, activity-coefficient, and relative viscosity data, the hydration number for choline chloride has been calculated to be 2·1 which is in satisfactory agreement with the value of 2·7 found from isopiestic data alone.

Additions and Corrections - Activity, Density, and Relative Viscosity Data for Several Amino Acids, Lactamide, and Raffinose in Aqueous Solution at 25 degrees - Correction

Additions and Corrections - Activity, Density, and Relative Viscosity Data for Several Amino Acids, Lactamide, and Raffinose in Aqueous Solution at 25 degrees - Correction

Activity, Density, and Relative Viscosity Data for Several Amino Acids, Lactamide, and Raffinose in Aqueous Solution at 25°

Activity, Density, and Relative Viscosity Data for Several Amino Acids, Lactamide, and Raffinose in Aqueous Solution at 25°

The Temperature Dependence of Viscosity for Water and Mercury

Smoothed values for the viscosities of water and mercury, as reported in the literature, show surprisingly large percentage deviations from the experimental data. Because water is frequently used as the calibrating fluid in viscometry, it was of interest to apply expressions, suggested by the theory of Eyring, for smoothing experimental data. It was of further interest to apply the Arrhenius expression for the variation of viscosity with temperature to the data for both water and mercury and to compare the closeness of fit with that obtained by the use of the aforementioned expressions. As judged by the Gaussian criterion of fit, an expression suggested by the Eyring theory provides smoothed values for the viscosities of both water and mercury which are believed to be more reliable than those in common use. This is especially true for the viscosity of water, for which relative viscosity data were first smoothed and then pinned to the recent value of 10.019±0.003 millipoises at 20°C as reported by Swindells and Coe. From other empirical equations relating densities and energies of vaporization to temperature, equations are derived for expressing the activation energies for viscous flow as a function of temperature.

Stabilisation of montmorillonite sols by chemical treatment. Part I. Properties of sodium and calcium montmorillonite sols

AbstractAccording to ultramicroscopical counting and relative viscosity data the micelles of Na and Ca montmorillonite sols are minute flat crystal plates with an average thickness corresponding to that of a packet of about five crystal lattice layers only with an average diameter‐thickness ratio of the order of a few hundred. This is corroborated by electronmicrographs and X‐ray studies.The average thickness of the micelles decreases with decreasing sol concentration, indicating a concentration‐dependent association‐dissociation equilibruim of the crystal lattice layers.Montmorillonite is a peculiar colloid in the sense that the platy micelles may be assumed to bear two basically different double layers, one on the surface of the lattice and a second at the broken lattice edges. The two double layer potentials may even have a different sign.