Physicochemical Experiments of Polysorbate 80 with Organic and Inorganic Additives in an Aqueous Solution

Aqueous solutions of nonionic surfactants behave differently than those of ionic surfactants. Micellar properties and structural characterization of Polysorbate 80 (commonly known as Tween 80) were investigated in the presence of different additives at different temperatures (303–323 K) by using cloud point (CP), densitometry, and viscometry techniques. Nonionic surfactant shows the optimum effect when used near their CP, as the presence of additives strongly influences them. The compounds or additives that break the structure of water will increase the CP, while those that help to build the water structure show a decrease in the CP. Adding ester, urea, and carbohydrates decreases the CP of Polysorbate 80, while alcohol and thiourea show the opposite trend. Density and viscosity measurements of Polysorbate 80 in the presence of monovalent salts (NaX, X = Cl^–, Br^–, \({\text{NO}}_{3}^{ - }\), and salicylate) confirmed the change in molecular structure.