Temperature and pressure dependence of the double layer capacity at the mercury-solution interface

1965 ◽  
Vol 61 ◽  
pp. 326 ◽  
Author(s):  
G. J. Hills ◽  
R. Payne
Keyword(s):  
Double Layer ◽  
Pressure Dependence ◽  
Solution Interface ◽  
Double Layer Capacity ◽  
Temperature And Pressure

Specific adsorption of sulfamate ions at the mercury/solution interface

1982 ◽  
Vol 60 (13) ◽  
pp. 1643-1647 ◽  
Author(s):  
Ernesto R. Gonzalez
Keyword(s):  
Ionic Strength ◽  
Activity Coefficient ◽  
Double Layer ◽  
Adsorbed Water ◽  
Water Molecules ◽  
Electrostatic Model ◽  
Solution Composition ◽  
Solution Interface ◽  
Double Layer Capacity ◽  
Mercury Electrodes

The adsorption of sulfamate ions on mercury electrodes has been studied by measuring the double layer capacity in constant ionic strength solutions of composition xM NH4SO3NH2 + (1−x)M NH4F. It was found that sulfamate ions are weakly adsorbed on mercury, the amount adsorbed being significant only for x > 0.1 at positive charges on the electrode. Because of this, the properties of the inner layer were found to be strongly dependent on the adsorbed water molecules and the structure of the diffuse layer. It was determined that the adsorption of sulfamate ions can be described by an isotherm based on the electrostatic model of the double layer. The possible effects of the activity coefficient variation with solution composition are discussed.

Adsorption and Condensation of Xanthine at the Mercury/Solution Interface

1998 ◽  
Vol 63 (12) ◽  
pp. 1977-1993 ◽  
Author(s):  
Viktor Dražan ◽  
Vladimír Vetterl
Keyword(s):  
Double Layer ◽  
Electrode Surface ◽  
Lattice Gas ◽  
Standard Gibbs Energy ◽  
Mercury Electrode ◽  
Ising Lattice ◽  
Compact Layer ◽  
Solution Interface ◽  
Double Layer Capacity ◽  
Lattice Gas Models

The adsorption and two-dimensional condensation of xanthine at the mercury electrode in 0.2 and 2 M NaCl was studied by electrode double layer capacity measurements. The condensation of xanthine molecules adsorbed at the electrode was observed at pH 6.0 and 7.4, but not at 9.0. The standard Gibbs energy of adsorption, energy of lateral interactions and the surface occupied by one xanthine molecule in a compact layer were calculated from the temperature dependence of the capacity pit using the Frumkin and Ising lattice gas models. The orientation of xanthine molecules in a compact layer at the electrode surface was estimated. At higher bulk concentrations of xanthine, the double layer capacity decreases to a very low value of about 1.5 mF cm-2, which might be an indication of the formation of a xanthine multilayer at the electrode surface.

Measurements of real non-Newtonian response for liquid lubricants under moderate pressures

2001 ◽  
Vol 215 (3) ◽  
pp. 223-233 ◽  
Author(s):  
S Bair
Keyword(s):  
Numerical Simulation ◽  
Kinetic Theory ◽  
Simple Shear ◽  
Pressure Dependence ◽  
Shear Stresses ◽  
Current Interest ◽  
Flow Properties ◽  
Power Law Fluid ◽  
Temperature And Pressure

A thorough characterization of all viscous flow properties relevant to steady simple shear was carried out for five liquid lubricants of current interest to tribology. Shear stresses were generated to values significant to concentrated contact lubrication. Two types of non-Newtonian response were observed: shear-thinning as a power-law fluid and near rate-independence. Functions and parameters were obtained for the temperature and pressure dependence of the viscosity and of the time constant for the Carreau-Yasuda equation. Results are consistent with free volume and kinetic theory, but directly contradict many assumptions currently utilized for numerical simulation and for extracting rheological properties from contact measurements.

Sign in / Sign up

Export Citation Format

Share Document