A pH-Responsive Foam Formulated with PAA/Gemini 12-2-12 Complexes

Autor: Hernán Martinelli, Claudia Domínguez, Marcos Fernández Leyes, Sergio Moya, Hernán Ritacco
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Colloids and Interfaces, Vol 5, Iss 3, p 37 (2021)
Druh dokumentu: article
ISSN: 2504-5377
DOI: 10.3390/colloids5030037
Popis: In the search for responsive complexes with potential applications in the formulation of smart dispersed systems such as foams, we hypothesized that a pH-responsive system could be formulated with polyacrylic acid (PAA) mixed with a cationic surfactant, Gemini 12-2-12 (G12). We studied PAA-G12 complexes at liquid–air interfaces by equilibrium and dynamic surface tension, surface rheology, and X-ray reflectometry (XRR). We found that complexes adsorb at the interfaces synergistically, lowering the equilibrium surface tension at surfactant concentrations well below the critical micelle concentration (cmc) of the surfactant. We studied the stability of foams formulated with the complexes as a function of pH. The foams respond reversibly to pH changes: at pH 3.5, they are very stable; at pH > 6, the complexes do not form foams at all. The data presented here demonstrate that foam formation and its pH responsiveness are due to interfacial dynamics.
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