Study of the depletant concentration on the rheology of concentrated nanoemulsions

Nanoemulsions are metastable colloidal dispersions with a wide range of applications in food, cosmetic, and pharmaceutical industries due to their unique structural properties. Gelation in nanoemulsions can effectively be used to expand their applications as rheology modifiers and to design highly structured porous materials. In this research, we study the colloidal gelation of concentrated nanoemulsion with the oil volume fraction of 50% and 60% in the presence of depletant molecules. The rheological properties of the concentrated nanoemulsions are studied at different concentration of polyethylene glycol diacrylate (PEGDA) as the depletant. The gelation behavior and the structure-flow relationship of nanoemulsions are examined through flow curve and oscillatory shear measurements. Due to the probable presence of polymer-surfactant complexation at the interface and in order to achieve a comprehensive knowledge of PEGDA effect on nanoemulsion behavior, the interfacial properties of different systems are also studied over time. These results offer a foundation for controlling the properties of colloidal systems and nanoemulsion-templated porous materials.