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| Home > Publications database > Isothermal Behavior of the Soret Effect in Nonionic Microemulsions: Size Variation by Using Different n-Alkanes |
| Home > Publications database > Isothermal Behavior of the Soret Effect in Nonionic Microemulsions: Size Variation by Using Different n-Alkanes |
| Conference Presentation (After Call) | FZJ-2015-02256 |
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2014
Abstract: In this work we investigate the thermodiffusion behavior of microemulsion droplets of the type H2O / n-alkane / C12E5 using the n-alkanes: n-octane, n-decane, n-dodecane and n-tetradecane [1]. In order to determine the thermodiffusion behavior of these microemulsion droplets, we apply the infrared thermal diffusion forced Rayleigh scattering technique. We measure the Soret coefficient S_T as function of the structure upon approaching the emulsification failure boundary (efb) and as a function of the radius of the spherical o/w-microemulsion droplets close to the efb. By varying the chain length of the n-alkanes we are able to study the thermodiffusion behavior of droplets of different sizes at the same temperature. In the investigated range a linear dependence of the Soret coefficient as function of the radius was found. Using a proposed relationship between the Soret coefficient and the temperature dependence of the interfacial tension, the transition layer, l, could be determined for the first time [2].Additionally, small angle neutron scattering (SANS) experiments are performed to determine the size and to examine in detail the shape of the microemulsion droplets, as the droplets are known to elongate with increasing temperature. Close to the efb the scattering curves could be quantitatively described by a combination of a spherical core-shell form factor and sticky hard sphere structure factor. [1] Naumann, P., Datta, S., Sottmann, T., Arlt, B., Frielinghaus, H. and Wiegand, S. Submitted to J. Phys. Chem.B.[2] Parola, A. and Piazza, R.; Particle Thermophoresis in Liquids Eur. Phys. J. E., 15, pp. 255-263, 2004.
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