Dresden 2006 – scientific programme
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DY: Dynamik und Statistische Physik
DY 46: Poster
DY 46.71: Poster
Thursday, March 30, 2006, 16:00–18:00, P1
Conductivity Measurements on Water in Oil Microemulsions — •Robert Wipf, Thomas Blochowiscz, Gustav Nyström, and Bernd Stühn — Institute of Condensed Matter Physics, Technical University Darmstadt, D-64289 Darmstadt
Water-in-oil microemulsions are thermodynamically stable mixtures of waterdroplets in a continuous oil phase. The water droplets are stabilized by a monomolecular surfactant layer. Surfactant molecules have a polar, hydrophilic headgroup and an apolar, lipophilic tail. The investigated microemulsion consists of water and decane with sodium bis(2-ethylhexyl)sulfosuccinate (AOT) as surfactant. Structure and dynamics of this system is well characterized by small-angle-X-ray and dynamic light scattering measurements. The conductivity of such systems shows a steep increase with volume fraction of droplets or temperature increasing over a certain critical value. This behavior can be attributed to a dynamic percolation phenomenon.[1]
Adding an amphiphilic triblock copolymer to a microemulsion leads to an interconnection of the droplets and thus to generation of a transient network. Here we will present our conductivity measurements on pure microemulsions and microemulsions containing polymer. We performed frequency and temperature dependent measurements in a range of 15∘C to 35∘C and 10−2Hz to 106Hz respectively. First we characterized the percolation transition in pure microemulsions. Then we investigated the influence of increasing polymer content on the ion transport and relaxation in the microemulsion was investigated.
[1] H. Kataoka et al.: J. Phys. Chem. B 2003, 107, 12542-12548