Equilibrium and Dynamic Surface Properties of Cationic/Anionic Surfactant Mixtures Based on Carboxylate Gemini Surfactant

Abstract

The equilibrium and dynamic surface properties of cationic/anionic surfactant mixtures of carboxylate gemini surfactant (CGS12) and quaternary ammonium salts with different alkyl chain lengths were investigated, and the synergistic properties and solubilization capacity toward phenanthrene of these mixtures were evaluated. Results show that all cationic/anionic surfactant mixtures exhibit negative interaction parameters, indicating the strong synergistic effects in the reduction of surface tension and the formation of micelles. When the mixing ratio is 1:1, the surface tension reaches the minimum value. Moreover, as the alkyl chain length increases, the interaction parameters become more negative. In addition, the thermodynamic parameters suggest that the formation of mixed micelles is exothermic with a positive change in entropy. The tendency of dynamic surface tension curves of these mixtures is similar to that of pure CGS12. At the same concentration, these mixtures exhibit a higher adsorption rate than pure surfactants, and a lower adsorption potential barrier than cationic surfactants. However, for the CGS12/stearyltrimethylammonium bromide mixture, the drop rate constant of surface tension is lower than that of either component. Compared with the pure surfactant solutions, the cationic/anionic surfactant mixtures exhibit higher solubilization capacity toward phenanthrene. As the length of the alkyl chain increases, the solubilization capacity of the mixed cationic/anionic surfactant increases.

Treatment of Oily Wastewater Using a Hyperbranched Poly (amido amine) Demulsifier with 1,4‐Phenylene Diamine as Central Core

“…It is observed that the surface tension decreases rapidly at low demulsifier concentrations, and then has a nearly constant value, indicating the formation of micelles. The intersection of the two straight lines in the γ‐lgC plots is defined as the critical micelle concentration (CMC) . With the increase in the PPDA concentration, the PPDA molecules aggregate into micelles and the interaction between the molecules finally reaches equilibrium, so that the surface tension reaches a nearly constant value.…”

Effects of inorganic metal ions on the mixture of single polyoxyethylene chain carboxylate surfactant and Gemini quaternary ammonium surfactant

“…Therefore, when mixed, the two hydrophilic head groups with heterogeneous charges will produce strong electrostatic interaction, which will significantly reduce the electrostatic repulsion between molecules in the mixed monolayer and mixed micelles, increase the saturated adsorption capacity of surfactants and greatly improve the surface activity. [1][2][3][4][5] In addition, this interaction drives the hydrophilic head groups of anionic and cationic surfactants to associate closely to form a phospholipid-like structure so that it can self-assemble into rich aggregate structures such as vesicles without any external work. [6][7][8] However, excessive strong interaction will also make anionic and cationic surfactants form catanionic surfactant complex (precipitate) difficult to dissociate, thus losing surface activity and affecting its further application in practice.…”

Demulsification of oil‐in‐water emulsions using hyperbranched poly(amido amine) demulsifiers with 4,4‐diaminodiphenyl methane as initial cores

“…Demulsifiers are usually amphiphilic compounds that have both hydrophobic and hydrophilic groups. They can break down the oil‐in‐water emulsions by replacing the intrinsic interface active materials on the interface and changing the surface wettability of the solid particles to promote the coalescence and flocculation of the oil droplets . Demulsifiers can be divided into three categories of the anionic, cationic, and nonionic demulsifiers.…”