Thermodynamic properties of aqueous solutions of surfactants: molar heat capacities and volumes

Abstract

We have measured heat capacities and densities of aqueous solutions of six ionic surfactants and one non-ionic surfactant at molalities both smaller and larger than the critical micelle molalities. Surfactants investigated were sodium octanoate, sodium laurate, sodium dodecylsulfate, sodium bis-2-ethylhexylsulfosuccinate (Aerosol ot or aot), sodium oleate, dodecylammonium chloride, and N,N-dimethyldodecylamine oxide. Results of all such measurements at 298.15 K have been reported in the form of apparent molar heat capacities and apparent molar volumes, from which it is possible to obtain corresponding partial molar properties.