Perturbation of SDS and CTAB micelles by complexation with poly(ethylene oxide) and poly(propylene oxide)

Abstract

Pseudo-first-order rate constants have been determined for the neutral hydrolysis of l-benzoyl-3-phenyl-1,2,4-triazole in aqueous solutions in the presence of SDS and CTAB micelles and SDS-PEO, SDS-PPO, and CTAB-PPO mixed micelles. The micellar rate inhibition of the hydrolysis is clearly modified as a result of micelle-polymer complexation, the effects being rather specific for the nature of the surfactant and the polymer. The kinetic data were analyzed by a simple pseudophase model. The results revealed stabilization of the micelles by interaction with the polymer and polymer-induced microenvironmental changes at the micellar binding sites of the substrate. Results from conductivity measurements facilitated the interpretation of the kinetic data.

Construction of surfactant-membrane electrodes selective for sodium dodecyl sulfate in poly(ethylene oxide)-surfactant mixtures

“…It is well documented that, in the PEO-SDS complexes, the micellar clusters are smaller aggregates and, as a consequence, they are more dissociated than regular SDS micelles. 4,11,20,23 Therefore, based on this, in comparison to the SDS solution in the absence o PEO, the differences in ionic content explain the higher E values obtained for the solution containing the polymer.…”

“…Finally, for surfactant concentrations above the psp, the formation of only regular SDS micelles in equilibrium with PEO-SDS complexes is generally accepted. 7,8,11 This evidence is supported by the fact that, above the psp, for the properties analyzed such as the electrical conductivity 20,21 and surface tension, 7,22 in the presence or absence of PEO, the methods exhibit the same slope for the conductivity-[SDS] plots and the same surface tension values for the surface tension-[SDS] plots, respectively. Based on the above considerations, the same E values obtained in the presence and absence of PEO (Figures 3 and 4), at higher SDS concentrations, strongly indicates also here the formation of only regular SDS micelles.…”

“…These results are in agreement with the behavior of the electrical conductivity-[SDS] plots, which increase linearly with SDS concentration and the slopes are independent of PEO concentration. 4,17,20,21,24 …”

Autoassociação de misturas dos Surfactantes Dodecanoato de Sódio (SDoD) e Decanoato de Sódio (SDeC) com o Polímero Hidrofobicamente Modificado Etil(Hidroxietil)Celulose (EHEC)

“…30 acordo com a interpretação clássica dada a este perfil. 10,21,[33][34][35][36] As Figuras 2 e 3 mostram os perfis de condutividade elétrica de três misturas de SDoD e SDeC com composições diferentes, em presença de 0,1 e 0,2% (m/v) de EHEC, respectivamente. Na presença de EHEC, os perfis de condutividade das diferentes misturas de SDoD e SDeC apresentam três regiões lineares e duas descontinuidades: a primeira descontinuidade está associada à concentração de surfactante a partir da qual se verifica o início da associação cooperativa entre o polímero e a mistura de surfactantes, cac; a segunda descontinuidade refere-se à concentração total de surfactante a partir da qual se verifica a saturação do polímero pelas moléculas de surfactante, psp.…”

The role of polymer flexibility on the interaction with surfactant micelles: poly(vinyl alcohol) and sodium dodecyl sulphate aqueous micelle interactions studied by dynamic fluorescence quenching

“…Among anionic surfactant -polymer systems, sodium dodecyl sulphate (SDS) -poly(ethy1ene oxide) (PEO) is one of the most studied, both by classical and modern methods (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). The system SDS -poly(viny1 alcohol) (PVA), on the other hand, has been studied mainly by classical methods (1 1, 21-25).…”