Regensburg 2013 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 49: Colloids and Complex Liquids III
CPP 49.7: Vortrag
Freitag, 15. März 2013, 11:15–11:30, H40
SANS study of polymer loaded microemulsions — •Andreas Weber1, Henrich Frielinghaus2, and Bernd Stühn1 — 1Experimental Condensed Matter Physics, TU Darmstadt, Germany — 2Jülich Centre for Neutron Science, Germany
The interactions between polymers and soft surfactant layers are subject of current research interest. We study these interactions in microemulsions in the droplet phase, where surfactant stabilized droplets of water are dispersed in a matrix of octane. Small angle neutron scattering experiments allowed us to observe directly the effect of a polymer on an anionic or non-ionic surfactant layer. To microemulsion droplets of different sizes composed by either AOT or C12E4 we added different amounts of the hydrophilic polymer PEG. While matrix and water core of the microemulsion were deuterated, the surfactant and polymer were protonated, thus, allowing us to observe the surfactant shell influenced by the polymer. We observe, as predicted by theory and indirect measurements such as dielectric spectroscopy, that the polymer interacts differently with a nonionic or a anionic surfactant shell: Apart from an increase of polydispersity of the droplets in both cases, in the former case the addition of polymer seems not to affect the surfactant shell. In the latter case, the obtained scattering data show that the anionic surfactant layer is strongly influenced. We develop a model describing the scattering of the polymer inside the polymer loaded droplet and fit it to the data. The obtained results are compared to small angle x-ray scattering, dynamic light scattering and dielectric spectroscopy experiments on this system done in our group.