Structure and Viscoelastic Properties of Lamellar Phase Formed in Aerosol OT / Water Binary Systems
1997 Volume 25 Issue 4 Pages 223-225
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1997 Volume 25 Issue 4 Pages 223-225
Rheological properties and structure of the lamellar phase formed in AOT/water binary systems have been investigated using dynamic viscoelastic measurements and small angle X-ray scattering (SAXS). The lamellar repeat distance L is linearly dependent on the water/AOT weight fraction ratio Φ, suggesting that the thickness of AOT bilayer lA and the surface area per AOT molecule SA is independent of AOT concentration. From the slope and intercept of plots of L against Φ, the values of lA, density of AOT bilayer ρA, and SA can be obtained respectively as 17.9Å, 1.28 g/cm3, and 64.5Å2. These values are consistent with the AOT molecular formula. The values of storage modulus G′ and loss modulus G″ of the AOT/water bilayer systems are almost constant over wide range of frequency, and G′ is always higher than G″ for all the samples. And G′ increases with increasing AOT concentration. These fact suggest that the lamellar structure is three-dimensionally extended over the systems.
