The adsorption of sodium dodecyl sulphate at the oil-water interface and application of the Gibbs equation

Abstract

The use of the Gibbs equation in determining the adsorption of a surface-active electrolyte is discussed. The effect of excess inorganic salt on the amounts of sodium dodecyl sulphate adsorbed at the interface of a standard decane emulsion has been determined. Interfacial tension measurements on the same systems show that results consistent with the direct adsorption data are obtained, provided that a factor of 2 is included in the approximate form of the Gibbs equation for solutions containing no inorganic salt. Equations of state for the adsorbed films are considered.

Kinetics of Adsorption of Cationic Surfactants at Silica-Water Interface

“…We may thus conclude that the effect of hydration of silica or CTAB, respectively, on the value of k 1 is not large. Also k 1 We also find from Tables 1 and 2 that magnitude of k 2 in most cases is five-to tenfold smaller than k 1 . In the case of our studies of the kinetics of protein adsorption at solid -liquid interfaces, the process is found to possess two steps with two rate constants k 1 and k 2 , and k 2 is threeto eightfold less than that of the value of k 1 .…”

“…The values of G e 2 were calcuof concentration, and these values were reported elsewhere lated using Eq. [1] replacing C 2 by C e 2 . The standard devia- (43).…”

Entropic, electrostatic, and interfacial regimes in concentrated disordered ionic emulsions

“…In this calculation, we have used a measured and reported value of σ e ≈ 2 e/nm 2 for the adsorbed surface density of dodecyl sulfate anions (DS−) at the interface of decane and water at c 0 = [SDS] = 10 mM (Cockbain 1954). Differences in the dispersed phase compositions and differences in the experimental system from the assumed boundary conditions inherent in Grahame's equation could account for at least some of the difference between the estimated and fitted values of ψ 0 .…”

Effect of Foam Films on Gas Diffusion

“…, where σ 0 represents σ at the lowest surfactant concentration, taken approximately to be 80 (Å) 2 for the practical stability of SDS stabilized films (25). The incorporation of ψ 0 (C e ) and E a (θ) into the prediction of the film permeability is proposed here for the first time.…”