Adsorption studies of nonionic surfactants onto polyvinyltoluene microlatexes in aqueous medium

Negatively charged polyvinyltoluene (PVT) microlatexes of various dimension s were prepared by polymerization of the corresponding vinyltoluene-in-wate r microemulsion precursors containing sodium dodecyl sulfate and n-pentanol . PVT microlatexes were used as adsorbents for adsorption of nonionic surfa ctants such as Tween 80, Tween 20, and Triton X-100. The extents of adsorpt ion were known from the differences in the diffusion coefficient of the PVT microlatexes containing a solubilized suitable electroactive probe. The su rface excess (Gamma), equilibrium constant of adsorption (K-ads), molecular cross-sectional surface area (sigma), intercalation ratio (kappa), etc., w ere determined for sodium dodecyl sulfate composition variation and ionic s trength effects. A surface reconstruction model was proposed to rationalize the results. (C) 2000 Academic Press.