Contribution of micelles to ionic strength of surfactant solution

Re-evaluated data of dissociation constants of alendronic, pamidronic and olpadronic acids

“…The activity coefficient of hydrogen ions used for the calculation of pK a2 of alendronic acid in micellar solution of CPC was set equal to the activity coefficient for aqueous solution of KCl. This was done because the problem of ionic strength calculation for micellar solutions has not been resolved, although it is known that ionic strength in micellar solutions is somewhat lower than total concentration of ionic surfactant [40]. The micellar media effect on pK a3 , pK a4 , pK a5 of investigated acids agreed with obtained in work [23] for structurally related gem-diphosphonic acids.…”

Aggregation of sodium dodecylsulfate in aqueous nitric acid medium

“…Shielding factor is sometimes used to reduce the contribution of ionic micelles to I. Burchfield and Woolley [20] derived equations for activity coefficients and osmotic coefficients of aqueous ionic surfactant solutions by treating these solutions as mixed electrolytes and reported that these equations become applicable to experimental data when shielding factor having values in the range 0.5-0.68 was used to shield the charge on the micelles. Jalšenjak [21] introduced a concentrationdependent shielding factor to assess the contribution of micelles to I of surfactant solution. Different values for shielding factor were also tested in the earlier studies [5,6] while analyzing the conductivity data of ionic surfactant solutions.…”

Micellar aggregation for ionic surfactant in pure solvent and electrolyte solution: Nonextensive thermodynamics approach

“…Generally, this phenomenon is ascribed to a putative reduction in the quantity of amphiphiles free in solution [48] or, more probably, to modification of the ionic strength of the medium [49].…”

“…Values of DS − and Na + activities were recently used by Jalsenjak [49] to discuss the contribution of micelles to the ionic strength of surfactant solution, by introducing a new definition of the concentration-dependent "shielding factor." The values of monomer and counterion activities calculated in this way are in better agreement than those calculated using Burchfield and Wooley's constant [3] with experimental values, but nevertheless do not give an exact description of the experimental reality.…”