III. The importance of diffusion in the adsorption process of some alcohols and acids in dilute aqueous solutions

On the importance of the purity of surfactant solutions in determining their adsorption kinetics

“…Figure 1 represents the "experimental" dependence (e-e) as well as a family of curves cx (t) which relate to different kinetic constants of the model of diffusion-kinetic-controlled adsorption. These dependencies are analogous to the results which Borwankar and Wasan [21] obtained for the dynamic surface tension of n-decanoic acid solutions when applying a corresponding kinetic model to the experimental data given by Defay and Hommelen [24,25]. The experimental findings of [24,25] may lead to the conclusion of a hindered adsorption [21].…”

“…These dependencies are analogous to the results which Borwankar and Wasan [21] obtained for the dynamic surface tension of n-decanoic acid solutions when applying a corresponding kinetic model to the experimental data given by Defay and Hommelen [24,25]. The experimental findings of [24,25] may lead to the conclusion of a hindered adsorption [21]. Just the same situation is met in the case of the above mentioned "theoretical" experiment, i. e. by the installation of an impurity in the surfactant solution system a hindered adsorption mechanism would be simulated for the true surfactant (main component).…”

Interfacial properties and foam stability effect of novel gemini-type surfactants in aqueous solutions

“…(3c) is ∼2.2 × 10 −14 m 2 s −1 , which is much lower than the literature values of the diffusion coefficient for surfactant molecules, which usually falls in the order of 10 −10 m 2 s −1 . Such a large difference in diffusion coefficient cannot be attributed to the higher molecular weight of GS alone, but probably, there exist an high adsorption energy barrier [12,[15][16][17], which means that not all the molecules diffusing to the interface get adsorbed.…”

Transient Surface Tension of an Expanding Liquid Sheet

“…If Marangoni stresses initially create a shear layer on the two faces of the film, the time of growth of this shear layer across the film is short compared to the transit time: it is of order e 2 /ν 1 , always smaller than 10 ms (sheet thickness at the rim being smaller than 0.1 mm according to Eqs. [6] and [7]), which is our minimum transit time. Hence the homogeneity of velocity in the film is a reasonable approximation.…”

“…The correct solution of the diffusion equations, accounting for the reversibility of the adsorption process at the interface, was given by these authors for diffusion processes (4). Measurements conducted with alcohols of different chain length are well accounted for by Ward and Tordai's law (5,6). However, diffusion is not the only ingredient involved in the repopulation process of the liquid surface by surfactant molecules.…”