Mixtures of anionic surfactants with single/triple polyoxyethylene chains and Gemini quaternary ammonium surfactant: interaction and surface activity studies

The combination of anionic and cationic surfactants can obtain high surface activity so that it has been widely used in many fields. However, the problem of ease to precipitate in the isoelectric mole ratio limits its further application. The introduction of polyoxyethylene chain into anionic surfactant and the use of Gemini quaternary ammonium surfactant can solve this problem origin from excessively strong interaction to a great extent while maintaining the best surface activity of the mixed system. Single polyoxyethylene chain carboxylate and triple polyoxyethylene chains sulfonate surfactants are mixed with Gemini quaternary ammonium surfactant respectively and their interactions are explored. The experimental results show that the complex of anionic surfactants with single or triple polyoxyethylene chains and Gemini quaternary ammonium surfactant can obtain high surface activity. And the polyoxyethylene group weakens the charge density of hydrophilic head groups of anionic surfactants. The branched polyoxyethylene chains will weaken this weakening effect. Excessively large steric hindrance of surfactant may reduce the stability and surface activity of mixed system. For anionic nonionic surfactants, the single chain structure and the appropriate numbers of polyoxyethylene groups are more conducive to compounding with Gemini quaternary ammonium surfactants to obtain the best surface activity and the most stable solution. (C) 2021 Elsevier B.V. All rights reserved.