Interfacial, thermodynamic, and performance properties of α‐sulfonato myristic acid methyl ester—hexaoxyethylene monododecyl ether mixed surfactants

Abstract

The interfacial, thermodynamic, and performance properties of the aqueous a-sulfonatomyristic acid methyl ester (MES)—hexaoxyethylene monododecyl ether (C12E6) mixedsurfactant system have been investigated. The critical micelle concentrations (cmcs) wereobtained by surface tension and conductivity measurements. The maximum surface excess(Gmax) and minimum area per molecule (Amin) were determined from surface tension (g)–logconcentration (log C) plots. The thermodynamic parameters of micellization and adsorptionwere computed. Micellar aggregation numbers (Nagg) of pure and mixed surfactant systemswere evaluated by fluorescence measurements. Interaction parameters between surfactantmolecules in mixed micelles were evaluated using Rubingh’s approach. The performanceproperties of pure and mixed surfactant systems viz. foaming, detergency, and viscosity werestudied. Cloud point (CP) determinations of the nonionic C12E6in the presence of electrolytes(NaCl, NaBr, and NaI) and nonelectrolytes like polyethylene glycols (MW 200, 300, and 400)were also carried out.