Influence of the salinity on the interfacial properties of a Brazilian crude oil–brine systems

•We report the effect of aging time at 40°C on the compressibility of the interface.•The elastic and viscous moduli increased with the salinity of the aqueous phase.•The salt leads to a stronger interfacial activity and emulsion stability. The main focus of the present work was to study the influence of the salinity of aqueous phase on the interfacial properties of a Brazilian crude oil/brine solutions. The pendant drop technique was used to conduct rheological dilatational studies, and a methodology for obtaining important parameters for the rheological study was also presented. The viscoelastic properties were evaluated through dynamic tests that were accomplished up to 24h. The influence of the interfacial film aging time at 40°C on the compressibility was also investigated. The results indicated that the values of the total interfacial elasticity and its components, viscous and elastic modulus, were enhanced with the increase of salt content of the brine solutions, suggesting that the salt induces the formation of a more rigid interfacial film. Also the presence of salt led to a stronger interfacial activity of the surfactants yielding higher interfacial elasticity and compressibility.