Surfactant-Like Behavior for the Adsorption of Mixtures of a Polycation and Two Different Zwitterionic Surfactants at the Water/Vapor Interface

Abstract

The bulk and interfacial properties of solutions formed by a polycation (i.e., poly(diallyl-dimethylammonium chloride), PDADMAC) and two different zwitterionic surfactants (i.e., coco-betaine (CB) and cocoamidopropyl-betaine (CAPB)) have been studied. The bulk aggregation of the polyelectrolyte and the two surfactants was analyzed by turbidity and electrophoretic mobility measurements, and the adsorption of the solutions at the fluid interface was studied by surface tension and interfacial dilational rheology measurements. Evidence of polymer–surfactant complex formation in bulk was only found when the number of surfactant molecules was closer to the number of charged monomers in solutions, which suggests that the electrostatic repulsion associated with the presence of a positively charged group in the surfactant hinders the association between PDADMAC and the zwitterionic surfactant for concentrations in which there are no micelles in solution. This lack of interaction in bulk is reflected in the absence of an influence of the polyelectrolyte in the interfacial properties of the mixtures, with the behavior being controlled by the presence of surfactant. This work has evidenced the significant importance of the different interactions involved in the system for controlling the interaction and complexation mechanisms of in polyelectrolyte–surfactant mixtures.

Polymethylmethacrylate derivatives Eudragit E100 and L100: Interactions and complexation with surfactants

“…Akanno et al 47 suggested the presence of two different regimes for PDADMAC‐zwitterionic surfactant binding. The first one concerns low surfactant concentrations where zwitterionic surfactant molecules bind to the polymer chains.…”

Evaporation of Sessile Droplets of Polyelectrolyte/Surfactant Mixtures on Silicon Wafers

“…The increase in the turbidity of the mixtures for the highest surfactant concentrations can be only explained by the formation of solid particles due to the polyelectrolyte-surfactant association. This is only possible assuming that the formation of kineticallytrapped aggregates occurs due to the Marangoni stresses associated with a local excess of surfactant molecules during the initial stages of the mixing procedure [64][65][66][67][68]. These kinetically-trapped aggregates remain intact upon dilution and present a quasi-neutral inner core formed mainly of surfactant molecules bound to the polymer monomers, where the external region appears positively charged, i.e., formed by non-associated monomers.…”

Physicochemical Aspects of the Performance of Hair-Conditioning Formulations

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