The Study of Interface Tension and Phase Behavior of C₁₂BE/Oil/Wtaer/Alcohol System

A modified method was used to synthesis and purify zwitteronic surfactant dodecylbetaine C₁₂BE,and the isoelectric point of C₁₂BE was detemined to be pH=4.9.When pH＜4.9,the molecule appears to be cationic surfactant,and if pH≥4.9,be inner salt with no charge.The affection of pH on the interface activity of C₁₂BE was studied.And the influences to the phase behavior of C₁₂BE/water/oil/alcohol coursed by the type and concentration of alcohol,saltness,pH of water were investigated.Characteristic parameters of middle microemulsion had been got such as γ_MW, a^*,a₁,a₂, et al..