STUDY ON THE ADSORPTION AND THE MICELLE FORMATION OF A (DECYLSULFINYL)ETHANOL AND (OCTYLSULFINYL)ETHANOL MIXTURE

The surface tension y of the aqueous solution of a (decylsulfinyl)ethanol (DeSE) and (octylsulfinyl)ethanol (OSE) mixture was measured as a function of its total molality m and composition X2 at 298.15 K under atmospheric pressure. The surface density ɼH and composition X2H of the surfactant mixture in the adsorbed film were evaluated by applying the thermodynamic equations to the surface tension values measured. At the critical micelle concentration (cmc), furthermore, the composition in the micelle, X2M, and the composition difference X2M - X2H,cmc were evaluated respectively by use of the cmc vs X, and 7cmc vs X2 curves, where X2H,cmc and ^cmc represent the values of X2H and y at the cmc. The relations between X2 and X2H and between X2 and X2M are expressed by diagrams similar to the threedimensional phase diagram, and the miscibility of surfactants in the adsorbed film and mixed micelle is discussed. © 1990, American Chemical Society. All rights reserved.