Modified Langmuir—Hinselwood kinetics for dynamic adsorption of surfactants at the air/water interface

Chang, Chien Hsiang; Franses, Elias I.

doi:10.1016/0166-6622(92)80230-y

Cited by 104 publications

(71 citation statements)

References 32 publications

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“…The best-fitted values of k a varied with concentration, which was also observed elsewhere (Chang and Franses, 1992). The mixed model required the lateral interaction factor (non-zero A) to improve the fitting.…”

Section: Diffusion-kinetic-mixed Modelmentioning

confidence: 83%

Dynamic adsorption of octanols at air/water interface

Phan

2010

Can J Chem Eng

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The dynamic adsorptions of 1-, 2-and 3-octanols at air/water interface were monitored using pendant drop method. It has been found that 1-octanol had strongest interfacial effects, yet slowest rate of adsorption. The experimental data were compared with diffusion-controlled and diffusion-kinetic-mixed models. Excepting 3-octanol at 1 mM, all systems required kinetic step. The effective kinetic constant was found varying with the concentration and the carbinol position. The results highlighted the influence of hydrophobic tails on the dynamic adsorption.Les adsorptions dynamiques de 1-, 2-et 3-octanolsà l'interface air/eau ontété suiviesà l'aide de la méthode de la goutte pendante. On a découvert que 1-octanol présente les effets interfaciaux les plus forts, mais le taux d'adsorption le plus lent. Les données expérimentales ontété comparées a l'aide de modèles par diffusion contrôlée età mélange diffusion-cinétique.À l'exception de 3-octanolà 1 mM, tous les systèmes ont nécessité uneétape cinétique. On a trouvé que la constante cinétique efficace varie avec la concentration et la position du carbinol. Les résultats ont mis eń evidence l'influence des queues hydrophobes sur l'adsorption dynamique.

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Section: Diffusion-kinetic-mixed Modelmentioning

confidence: 83%

Dynamic adsorption of octanols at air/water interface

Phan

2010

Can J Chem Eng

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“…In equilibrium, the variations (3.5) and (3.6) vanish, and we recover the Boltzmann distributions, 10) and the adsorption isotherm,…”

Section: Thermodynamic Equilibriummentioning

confidence: 99%

“…Various relations have been suggested, resembling equilibrium isotherms [4]- [6], or having a kinetic differential form [7]- [10]. Such theories have been quite successful in describing the experimentally observed adsorption of common non-ionic surfactants.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of Surfactant Adsorption at Fluid−Fluid Interfaces

1996

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We present a theory for the kinetics of surfactant adsorption at the interface between an aqueous solution and another fluid (air, oil) phase. The model relies on a free-energy formulation. It describes both the diffusive transport of surfactant molecules from the bulk solution to the interface, and the kinetics taking place at the interface itself. When applied to non-ionic surfactant systems, the theory recovers results of previous models, justify their assumptions and predicts a diffusion-limited adsorption, in accord with experiments. For salt-free ionic surfactant solutions, electrostatic interactions are shown to drastically affect the kinetics. The adsorption in this case is predicted to be kinetically limited, and the theory accounts for unusual experimental results obtained recently for the dynamic surface tension of such systems. Addition of salt to an ionic surfactant solution leads to screening of the electrostatic interactions and to a diffusion-limited adsorption. In addition, the free-energy formulation offers a general method for relating the dynamic surface tension to surface coverage. Unlike previous models, it does not rely on equilibrium relations which are shown in some cases to be invalid out of equilibrium.

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“…While in the nonequilibrium case there is a dependence of the kinetic constants on concentration, 33 one can approximate the nonequilibrium surfactant dynamics with the Langmuir-Hinshelwood equation, valid below CMC, for the surfactant surface concentration ⌫: …”

Section: A Physical Properties Of Sdsmentioning

confidence: 99%

Experimental study of substrate roughness and surfactant effects on the Landau-Levich law

Krechetnikov

Homsy

2005

Physics of Fluids

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In this work we present an experimental study of deviations from the classical Landau-Levich law in the problem of dip coating. Among the examined causes leading to deviations are the nature of the liquid-gas and liquid-solid interfaces. The thickness of the coating film created by withdrawal of a plate from a bath was measured gravimetrically over a wide range of capillary numbers for both smooth and well-characterized rough substrates, and for clean and surfactant interface cases. In view of the dependence of the lifetime of a film on the type of liquid and substrate, and liquid-gas and liquid-solid interfaces, we characterized the range of measurability of the film thickness in the parameter space defined by the withdrawal capillary number, the surfactant concentration, and substrate roughness size. We then study experimentally the effect of a film thickening due to the presence of surfactants. Our recent theory based on a purely hydrodynamic role of the surface active substance suggests that there is a sorption-controlled coating regime in which Marangoni effects should lead to film thinning. However, our experiments conducted in this regime demonstrate film thickening, calling into question the conventional wisdom, which is that Marangoni stresses ͑as accounted by the conventional interfacial boundary conditions͒ lead to film thickening. Next we examine the effect of well-characterized substrate roughness on the coated film thickness, which also reveals its influence on wetting-related processes and an effective boundary condition at the wall. In particular, it is found that roughness results in a significant thickening of the film relative to that on a smooth substrate and a different power of capillary number than the classical Landau-Levich law.

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Modified Langmuir—Hinselwood kinetics for dynamic adsorption of surfactants at the air/water interface

Cited by 104 publications

References 32 publications

Dynamic adsorption of octanols at air/water interface

Dynamic adsorption of octanols at air/water interface

Kinetics of Surfactant Adsorption at Fluid−Fluid Interfaces

Experimental study of substrate roughness and surfactant effects on the Landau-Levich law

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