Lucassen-Reynders

E. H. Lucassen-Reynders, A., Anionic Sufactants Physical Chemisty of Suf actant Actions, Sufactant Science Series, Vol. 11, Marcel Dekker, Inc., Basel,... 

Anionic Surfactants Physical Chemistry of Surfactant Action, edited by E. H. Lucassen-Reynders... 

The dynamic surface tension of a monolayer may be defined as the response of a film in an initial state of static quasi-equilibrium to a sudden change in surface area. If the area of the film-covered interface is altered at a rapid rate, the monolayer may not readjust to its original conformation quickly enough to maintain the quasi-equilibrium surface pressure. It is for this reason that properly reported II/A isotherms for most monolayers are repeated at several compression/expansion rates. The reasons for this lag in equilibration time are complex combinations of shear and dilational viscosities, elasticity, and isothermal compressibility (Manheimer and Schechter, 1970 Margoni, 1871 Lucassen-Reynders et al., 1974). Furthermore, consideration of dynamic surface tension in insoluble monolayers assumes that the monolayer is indeed insoluble and stable throughout the perturbation if not, a myriad of contributions from monolayer collapse to monomer dissolution may complicate the situation further. Although theoretical models of dynamic surface tension effects have been presented, there have been very few attempts at experimental investigation of these time-dependent phenomena in spread monolayer films. 

These assumptions have been expanded upon (Shah and Capps, 1968 Lucassen-Reynders, 1973 Rakshit and Zografi, 1980), especially in regard to the application of the ideal mixing relationship in gaseous films (Pagano and Gershfeld, 1972). It has been pointed out that water may contribute to the energetics of film compression if the molecular structures of the surfactants are sufficiently different (Lucassen-Reynders, 1973). It must be noted that this treatment assumes that the compression process is reversible and the monolayer is truly stable thermodynamically. It must therefore be applied with considerable reservation in view of the hysteresis that is often found for II j A isotherms. 

The deviations from the Szyszkowski-Langmuir adsorption theory have led to the proposal of a munber of models for the equihbrium adsorption of surfactants at the gas-Uquid interface. The aim of this paper is to critically analyze the theories and assess their applicabihty to the adsorption of both ionic and nonionic surfactants at the gas-hquid interface. The thermodynamic approach of Butler [14] and the Lucassen-Reynders dividing surface [15] will be used to describe the adsorption layer state and adsorption isotherm as a function of partial molecular area for adsorbed nonionic surfactants. The traditional approach with the Gibbs dividing surface and Gibbs adsorption isotherm, and the Gouy-Chapman electrical double layer electrostatics will be used to describe the adsorption of ionic surfactants and ionic-nonionic surfactant mixtures. The fimdamental modeling of the adsorption processes and the molecular interactions in the adsorption layers will be developed to predict the parameters of the proposed models and improve the adsorption models for ionic surfactants. Finally, experimental data for surface tension will be used to validate the proposed adsorption models. 

The average To of the partial molar area for all components or all possible states at the interface is often used in conjunction with the Lucassen-Reynders dividing surface, which can be equivalently described as... 

The choice of the Lucassen-Reynders dividing surface has a number of advantages, including the fact that the contribution of non-ideahty of entropy... 

In the following, the Lucassen-Reynders dividing surface is used to obtain a number of significant adsorption models. 

The general approach of Butler and Lucassen-Reynders can now be employed for investigating additional effects of the adsorbed molecules. Two important effects are examined below [17]. 

Ionic surfactants are electrolytes dissociated in water, forming an electrical double layer consisting of counterions and co-ions at the interface. The Gouy-Chapman theory is used to model the double layer. In conjunction with the Gibbs adsorption equation and the equations of state, the theory allows the surfactant adsorption and the related interfacial properties to be determined [9,10] (The Gibbs adsorption model is certainly simpler than the Butler-Lucassen-Reynders model for this case.). 

Lucassen-Reynders EH, Van den Tempel M (1967) Chem Phys Appl Surf Active Subst 2 779... 

Fainerman VB, Lucassen-Reynders EH, Miller R (1998) Colloids Surfaces A 143 141... 

Lucassen-Reynders EH (1981) Anionic Surfactants. In Lucassen-Reynders EH (ed) Physical Chemistry of Surfactant Action. Marcel Dekker, New York... 

Lucassen-Reynders, E. H. in "Anionic Surfactants " Lucassen-Reynders, E. H., Ed. Marcel Dekker New York, 1981 p. 1,... 

Dilatational surface rheology is a less discriminating experimental technique. At air-water and sunflower oil-water interfaces, it is found (Lucassen-Reynders and Benjamins, 1999) that both disordered p-casein... 

Lucassen-Reynders, E.H., Benjamins, J. (1999). Dilational rheology of proteins adsorbed at fluid interfaces. In Dickinson, E., Rodriguez Patino, J.M. (Eds). Food Emulsions and Foams Interfaces, Interactions and Stability, Cambridge, UK Royal Society of Chemistry, pp. 195-206. 

HALL, D.G. and TIDDY, G.J.T., Surfactant solutions dilute and concentrated , in LUCASSEN-REYNDERS, E.H. (editor), Anionic Surfactants, 11, 55-108, Dekker (1981)... 

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