The Surface and Thermodynamic Properties of Ethoxylated Sodium Monoalkyl Sulfosuccinate Surfactants

Abstract

A series of ethoxylated sodium monooctyl sulfosuccinates [E(n)SMOSS] and ethoxylated sodium monolauryl sulfosuccinates [E(n)SMLSS] have different units of ethylene oxide (n = 9, 14, 23) were synthesized. The surface and thermodynamic properties of these surfactants have been compared with sodium dioctyl sulfosuccinate surfactant (SDOSS) as a commonly used surfactant. The surface tension measurements at 25, 35, 45, and 55°C were used to determine of the critical micelle concentration (CMC) and surface active properties of these surfactants. The effect of the ethylene oxide (EO) unit and the alkyl chain length on the surface properties for the prepared surfactants was studied. The results show that the ethoxylated sodium monoalkyl sulfosuccinates generally have lower values of CMC than that of sodium dioctyl sulfosuccinate. The values of surface active parameters indicate that the ethoxylated sodium monooctyl sulfosuccinates and ethoxylated sodium monolauryl sulfosuccinates surfactants have adsorption properties better than the sodium dioctyl sulfosuccinate surfactant as a resulted presence of ethylene oxide in molecules of the prepared surfactants. The thermodynamic parameters show that the (EO) unites in the chemical structure of ethoxylated sodium monoalkyl sulfosuccinate surfactants improve their micellization and adsorption properties.