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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 38: Poster: Colloids and Complex Liquids

CPP 38.9: Poster

Wednesday, March 16, 2011, 17:00–19:00, P2

Interactions between polymers and curved surfactant layers — •Andreas Weber, Shun Yu, Tinka Spehr, and Bernd Stühn — Institut für Festkörperphysik, TU Darmstadt

We study the interaction between polymers and curved surfactant layers in microemulsions in the droplet phase, where surfactant stabilized droplets of water are dispersed in a matrix of oil. To study the difference between ionic and non-ionic surfactants we use either an ionic surfactant (AOT) or a non-ionic surfactant (C12E5, Brij®30). First, we examine the phase diagram of water-in-oil droplets without polymer. This is done by small angle X-ray scattering (SAXS) and light transmission experiments, where the turbidity point and thus the stability of the microemulsion is measured as a function of temperature. Then, to investigate the interaction between polymer and the curved surfactant layer, we add the hydrophilic polymer Polyethylene glycol (PEG). The location of the PEG inside the droplet is predicted to depend on the nature of the surfactant: While the PEG is expected to adsorb to the layer of the ionic surfactant AOT, in non-ionic microemulsions the PEG is supposed to be located in the water core away from the surfactant layer. SAXS is used to investigate the structure of the polymer loaded micelles and possible deformations of the droplets, dynamic light scattering and dielectric spectroscopy provide information concerning the dynamics of the droplets and the surfactant interface.