Acta Phys. -Chim. Sin. ›› 2001, Vol. 17 ›› Issue (02): 144-149.doi: 10.3866/PKU.WHXB20010211

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Density, Turbidity and Microscopic Structure of AOT/H2O/oil Microemulsions

Li Peng;An Xue-Qin;Shen Wei-Guo   

  1. Department of Chemistry, Lanzhou University, Lanzhou 730000
  • Received:2000-07-03 Revised:2000-09-01 Published:2001-02-15
  • Contact: Shen Wei-Guo

Abstract: Methods for study the microscopic properties of droplets in microemulsions by precise measurements of density, refractive index and turbidity have been established. The structural and interaction parameters of droplets in AOT/H2O/toluene microemulsions with molar ratio r of water to surfactant being 10.5 and 12 have been investigated and the molecular length L of AOT has been found to be 1.07 nm. The dependence of phaseseparation temperature on r has been discussed in terms of the interaction between droplets. With L=1.07 nm, microscopic structures of droplets of the two microemulsion systems of AOT/H2O/toluene and AOT/H2O/cyclohexane at various values of r have been investigated by measurements of density only. The results are excellently consistent with reported values. It has also been found that the density of water in droplets was significantly larger than that of free water, and was varied with the solvents, while the configuration of AOT molecule kept unvaried.

Key words: Microemulsion, Microscopic structures, Density, Turbidity