Volumetric Properties of Sodium Lauroylsarcosinate in Aqueous Alcohol Solutions of Methanol, Ethanol, and 1‑Propanol

The work attempts to gain an insight into the solution behavior of a biocompatible surfactant, sodium lauroylsarcosinate (SLS), in aqueous alcohol media at practically used concentrations of SLS (>CMC) where the solute–solute and solute–solvent interactions of surfactant aggregates are expected to be different from that between the solvent and the constituent monomers. The study of volumetric properties stresses the importance of hydrophilic and hydrophobic interactions operative between the SLS molecules and between SLS and the solvent. Moreover, it is interesting to observe how the dominance of electrostatic interactions fades and that of hydrophobic interactions rises as the concentration of SLS is progressively increased. Also, the study of standard apparent molar volumes, and the standard volumes of transfer offers a convenient way for accounting the differences between the alcohols which stems from their differing hydrophobicity.