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

Abstract

Abstract:The interactions between poly(viny1 alcohol) and the surfactant sodium dodecyl sulphate in aqueous solutions have been investigated by means of static and dynamic fluorescence measurements. By static fluorescence measurements the onset of interaction, the critical aggregation concentration, is determined to be 6.5 mM at 20°C and 7.0 mM at 40°C. By dynamic fluorescence measurements without added quencher the influence on the lifetime of the fluorescent probe, pyrene, by the presence of the polymer is investigated. From measurements with an added quencher, dimethylbenzophenone, the surfactant aggregation numbers of the micellar aggregates formed upon interaction between the surfactant and the polymer and the quenching rate constant are obtained. At the two polymer concentrations, i.e., 0.2% and 2.0%, the surfactant aggregation numbers at low surfactant concentration are very small, but increase rapidly with increasing surfactant concentration. Comparisons are made with results from a system where poly(ethy1ene oxide) instead of poly(viny1 alcohol) is the polymer.Key words: dynamic fluorescence quenching, polymer-surfactant interactions, aggregation numbers. R6urn6: Faisant appel a des mesures de fluorescence statique et dynamique, on a examine les interactions entre l'alcool polyvinylique et l'agent tensioactif dodecylsulfate de sodium, en solutions aqueuses. Sur la base de mesures de fluorescence statique, on a determine qu'au dkbut des interactions, la concentration critique d'agrkgation est Cgale B 6,s mM B 20°C et 2 7,O mM i 40°C. Utilisant des mesures de fluorescence dynamique sans addition de dksactivant, on a CtudiC l'influence du polymkre sur le temps de vie de la sonde fluorescente, pyrkne. Sur la base de mesures effectuees en presence de dimtthylbenzophCnone agissant comme desactivant, on a pu determiner la constante de vitesse de dksactivation et les nombres d'agregation de l'agent tensioactif des agrkgats micellaires formCs lors de l'interaction entre l'agent tensioactif et le polymkre. Aux deux concentrations du polymkre, B savoir 0,2 et 2,0%, on realise que les nombres d'agrkgation de l'agent de surface sont trks faibles i la faible concentration de l'agent tensioactif, mais qu'ils augmentent rapidement avec une augmentation de la concentration de l'agent tensioactif. On fait des comparaisons avec les rksultats obtenus avec un systkme dans lequel le polymkre est du poly(oxyde d'tthylkne) au lieu de l'alcool polyvinylique.

Effects of Different Stabilizers on Miniemulsion Methyl Methacrylate Polymerizations

“…The stabilizing performances of PVA and Pluronic F-127 were compared to each other in different practical systems and differences were assigned to the lower hydrophilicity and flexibility of PVA chains. [43] Particularly, Takasu et al [44] reported the CMC value of 8.0 × 10 −4 g.mL −1 for aqueous PVA solutions at room temperature through surface-tension measurements. As one can see, availability of CMC data of surfactants in complex reaction mixtures at actual reaction temperatures is scarce.…”

The Role of the Carboxylate Head Group in the Interaction of Sodium Dodecanoate with Poly(ethylene oxide) Investigated by Electrical Conductivity, Viscosity, and Aggregation Number Measurements

“…In this respect, most aggregation numbers that have been reported were obtained at surfactant or polymer concentrations where the results were probably a weighted average due to a mixture of regular micelles and polymer-surfactant complexes in solution (29,30). Recently we have shown, for PEO-sulfate surfactant systems, that at high PEO concentration, [PEO] = 0.10 M, it is possible to obtain constant n values in the range of cac-psp (16).…”

A New Strictly Alternating Comblike Amphiphilic Polymer Based on PEG. 2. Associative Behavior of a High Molecular Weight Sample and Interaction with SDS

“…The viscosity of the solutions renders the determination of the partition coefficient of DMBP between the micelles and the water phase impossible for our system at this polymer concentration. Van Stam et al reported a value of K D of 1900 M -1 for DMBP in 2% PEO and 20 mM SDS solution, where with [Q] m and [Q] aq the concentration of quencher in the micellar phase and in the water phase, respectively, and S m the concentration of surfactant in the micelles. For our system, S m can be expressed as S m = c p (M) + [SDS] m , where c p (M) is the concentration of hydrophobes from the polymer and [SDS] m is the concentration of SDS in the micelles.…”