Micellar properties of disodium 4-alkyl 3-sulfonatosuccinates, two-headed anionic surfactants

Abstract

Density, viscosity, conductance, dye solubility, and carbon-13 n.m.r. studies were performed in aqueous solution of three disodium 4-alkyl 3-sulfonatosuccinate surfactants at 25.0ºC. The CMC values were 0.33 mol dm^-3 for the hexyl homologue (dhss), 0.14 mol dm^-3 for the octyl homologue(doss), and 0.041 mol dm^-3 for the decyl homologue (ddss). The aggregation numbers determined viscometrically and conductimetrically were 15 for dhss, 29 for doss, and 50 for ddss. The volume changes upon micellization were 7.0 cm³ mol^-1 for dhss, 8.8 cm^-3 mol^-1 for doss, and 9.1 cm³ mol^-1for ddss. Binding constants for the dye pada to the micelle and the fractions of unbound counter-ion were also obtained. The two polar heads with their carbon linkage were likely in an aqueous environment in the doss micelles with the micelles themselves being spherical.