Surface activity of mixtures of narrow-range distributed alcohol oxyethylates and sodium dodecylbenzenesulfonate

Surface and interfacial tension, emulsion inversion temperature, and deterg ency were determined for mixtures of sodium dodecylbenzenesulfonate and nar row-range distributed alcohol C-12-C-14 oxyethylates of different hydrophil icity. The mixtures of ionic and nonionic surfactants behave similarly to n onionic and ionic surfactants at the air/water and hydrocarbon/water interf aces, respectively. The air/water interface is mainly occupied by nonionic surfactant molecules. However, the interfacial tensions for mixtures of non ionic and ionic surfactants are similar to those of sodium dodecylbenzenesu lfonate. Mixtures of narrow-range distributed oxyethylates and sodium dodec ylbenzenesulfonate have a higher detergency at 40 degrees C than individual components.