Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10609306 | European Polymer Journal | 2005 | 14 Pages |
Abstract
It is studied by spectrofluorimetry the association of ionized cationic micelles (cetyltrimethylammonium bromide, CTAB) with oppositely charged polyelectrolyte [sodium poly(styrenesulfonate), PSSNa]. CTAB provokes a change in the fluorescence intensity emitted by PSSNa. The investigated surfactants form micelle-like aggregates before critical micellar concentration (CMC). Two approaches (binding and partition equilibrium) are used to obtain the association constant, KA, number of CTAB molecules in a binding site, N, and apparent partition coefficient, Î. Analysis of the parameters as a function of polymer concentration and ionic strength μ is performed. The effect of μ shows an enhancement in association as μ decreases. Furthermore as CMC decreases with μ, experiments have to be performed at rather different CMCs. This causes KA and Î to increase with μ. The adsorption of polyelectrolyte on the micelle is also studied at the greatest μ using high-performance liquid chromatography (size-exclusion) for the first time, obtaining results similar to those found using spectrofluorimetry.
Related Topics
Physical Sciences and Engineering
Chemistry
Organic Chemistry
Authors
Francisco Torrens, Concepción Abad, Armando Codoñer, Rosa GarcıÌa-Lopera, AgustıÌn Campos,