This study aimed to develop microemulsion through of ternary system composed of brine (aqueous phase), vegetable oil (oil phase), and non-ionic polyethoxylated surfactants, T20 and T80. From the ternary diagrams obtained, two systems were chosen in the regions of microemulsion (Winsor IV) and, subsequently, were conducted rheological study, at different temperatures, and cloud point studies of these systems. The results showed that the microemulsion of T20/brine/vegetable oil presented thermal stability up to 53° C and microemulsions of T80/brine/vegetable oil of 72o C, that could be due a change in micelle morphology and cloud point of each microemulsion system. The rheological results indicated non-Newtonian behavior, adjusted by Herschel - Bulkley model.
