The critical behavior of pseudobinary microemulsion systems{water/sodium di(2-ethylhexyl)sulfo- succinate(AOT)/n-decane}with various droplet sizes was studied by measurements of refractive index. It was found that the critical exponentsβfor all systems approach 0.327 in a region sufficiently close to the critical temperature,which is consistent with 3D-Ising universality class.The critical temperatures linearly decrease as the dispersed droplet sizes increase.The critical amplitude almost linearly in- creases with increasing the dispersed droplet sizes.
Phase behavior of scCO2 microemul- sion formed with food grade surfactant sodium bis-(2-ethylhexyl) sulfosuccinate (AOT) was studied Critical microemulsion concentration (cμc) was de- duced from the dependence of pressure of cloud points on the concentration of surfactant AOT at con- stant temperature and water concentration. The re- sults show that there are transition points on the cloud point curve in a very narrow range of concen- tration of surfactant AOT. The transition points were changed with the temperature and water concentra- tion. These phenomena show that lower temperature is suitable to forming microemulsion droplet and the microemulsion with high water concentration is likely to absorb more surfactants to structure the interface.
