Adsorption and desorption of triton X-100 in polystyrene particles with different functionality - I. Adsorption study

A complete adsorption study of Triton X-100 onto latexes with different fun ctionality is presented. Three surfactant-free polystyrene latices with dif ferent chemical surface groups (sulfate, carboxyl, and amidine) were prepar ed. The pH of the liquid phase controls the surface charge, and hence this factor can be considered an important variable in this study. The adsorptio n isotherms show that an increase in the surface charge yields a decrease i n the amount of adsorbed surfactant. A descriptive mechanism of the adsorpt ion process which considers the presence of holes in the layer of adsorbed surfactant is presented for explaining the experimental results. On the oth er hand, the adsorption isotherms have been analyzed with two classical ads orption theories, those of Langmuir and Kronberg et al. Both theories give a good description of the results, but the latter offers more information a n the adsorption phenomena. (C) 2000 Academic Press.