Aggregation properties of sucrose fatty acid esters and some other sugar-based surfactants at different temperatures

Abstract

Measurements of density, viscosity and light scattering of aqueous solutions of food additive antimicrobial surfactants: sucrose capric acid ester (SMD) and sucrose lauric acid ester (SML) and some other sugar-based ones (n‑octyl‑β‑d‑glucopyranoside (OGP), n‑dodecyl‑β‑d‑glucopyranoside (DDGP), n‑dodecyl‑β‑d‑maltoside (DM)) as well as the fluorescence intensity of 8‑Anilino‑1‑naphthalene-sulfonic acid (ANS) and pyrene (Py) in aqueous solutions of the studied surfactants were carried out at different temperatures. On the basis of the obtained results the critical micelle concentration, average aggregation number, apparent and partial molar volume as well as the standard Gibbs free energy, standard enthalpy and entropy of micellization were determined. From the obtained thermodynamic parameters of micellization of studied sugar surfactants under different conditions, the temperature and type of surfactant impact on their aggregation properties were deduced. From the changes of the standard Gibbs free energy of micellization it results that the tendency of studied surfactants molecules to form micelles comes down as the temperature and surfactant tail length decrease. The presence and strength of the hydrogen bonds between the water molecules and sugar moiety in a surfactant molecule plays a decisive role in the micellization process of the studied sugar-based surfactants.