In this study, the functionality of [C8im-C4-imC8][Br2] gemini imidazolium ionic liquid (IL), as a new surfactant, on the equilibrium and dynamic interfacial tensions of crude oil-water was investigated. Different IL concentrations and temperatures were applied. Results showed a drastic reduction in equilibrium interfacial tension with the used gemini ionic liquid due to its strong amphiphilic nature and thus, providing high interfacial activity. The highest percentage of the IFT reduction was 97.8% at the critical micelle concentration of 0.20 mol dm−3. Temperature intensified this effect due to weakening the molecular forces between phases. The maximum decrease with temperature was about 15.2% for the lowest IL concentration and temperature effect was not significant at high IL concentrations, close to CMC. Also, both the IL concentration and temperature had effect on the dynamic interfacial tension and by increasing concentration, the required time to reach the equilibrium IFT was increased; however, at higher temperatures this time will be shortened.
