Synergism and Interfacial Property Study of Sodium Lauryl Ether Sulfate and Polysorbate 80 at the Air-Water Interface

Adsorption and micellization behavior of sodium lauryl ether sulfate (SLES) and Polysorbate 80 (PS80) was investigated using equilibrium and dynamic surface tension and foaming measurements. Critical micelle concentration (CMC) was determined using surface tension and dye (Sudan red III) solubilization method with the help of the Wilhelmy plate method and ultraviolet-visible spectroscopic method, respectively. The strength of the interaction for micellization and adsorption between the mixtures are calculated using the interaction parameter. The SLES-PS80 mixture shows synergistic interaction with = -8.0. The dynamic and foaming behavior at constant bulk concentration showed a higher t(*) value with lowest foaming at 50% mole fraction of SLES. The emulsification index (EI) of pure SLES, pure PS 80, and 1:1 SLES-PS 80 composition was studied using neem, karanja, and sunflower oils. Karanja and sunflower oils show a higher EI for mixture than the pure surfactants, whereas neem shows a lower EI for mixture than pure surfactants.