Aqueous Two‐Phase System (ATPS) Containing Gemini (12‐3‐12,2Br−) and SDS I: Phase Diagram and Properties of ATPS

Abstract

Two phases coexist in an aqueous system that contains the two surfactants cationic gemini 12‐3‐12,2Br− and anionic SDS. An aqueous two‐phase system (ATPS) is formed in a narrow region of the ternary phase diagram different from that of traditional aqueous cationic‐anionic surfactant systems. In that region, the molar ratio of gemini to SDS varies with the total concentration of surfactants. ATPS not only has higher stability but also has longer phase separation time for the new systems than that of the traditional system. Furthermore, the optical properties of ATPS are different at different total concentrations. All of these experimental observations can be attributed to the unique properties of gemini surfactant and the synergy between the cationic gemini surfactant and the anionic surfactant SDS.