Surfactants are widely used for academic and industrial purposes. For this reason, thermodynamic and physical properties of surfactant and cosurfactant mixtures can provide important information about the nature of the molecular interactions present. In this work, volumetric and transport data of surfactant binary mixtures of the ethanol + Igepal series (Igepal CO-520, Igepal CO-630, Igepal CO-720, and Igepal CA-720) were determined experimentally within a range of temperature of T = 293.15− 323.15 K, at atmospheric pressure. From these data, the following derivative properties have been calculated: the excess molar volume, viscosity deviation, and coefficient of thermal expansion. All of these mixtures showed that attractive intermolecular forces are dominant.

Surfactants are widely used in industrial applications associated with several solvents. Therefore, it is worthy to know the nature of the molecular interactions present in surfactants and cosurfactant mixtures, whose thermodynamic and physical properties can provide important information from an academic and industrial viewpoint. In this work, density and viscosity data of binary mixtures of toluene + Igepal series (Igepal CO-520, Igepal CO-630, Igepal CO-720, or Igepal CA-720) were experimentally determined within a range of temperature T = 293.15–333.15 K and at an atmospheric pressure of 101.325 kPa. From these data, the following derivative properties have been evaluated: excess molar volume, viscosity deviation, thermal expansion coefficient, partial molar volume, and excess thermal expansion coefficient. It was observed that all these mixtures showed the prevalence of dispersion intermolecular forces.