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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 39: Colloids and Complex Liquids II - Dynamics and Mechanical Properties

CPP 39.2: Vortrag

Donnerstag, 17. März 2011, 10:45–11:00, ZEU 222

Structure and Dynamics of AOT Microemulsions with Amphiphilic Diblock Copolymers — •Markus Appel, Robert Wipf, Tinka Spehr, and Bernd Stühn — Institut für Festkörperphysik, TU Darmstadt

We investigate the influence of amphiphilic diblock copolymers on structure and dynamics of the droplet phase of water-in-oil microemulsions based on the surfactant AOT. The size of the droplets is determined by small angle X-Ray scattering experiments, while broadband dielectric spectroscopy (1 Hz to 3 GHz) is used to probe micellar interactions. The temperature-dependent phenomenon of dynamic percolation can be used to estimate the bending modulus of the AOT layer, which is known to be influenced by certain hydrophilic polymers adsorbing to the surfactant layer [1]. Furthermore the dielectric relaxation process in the frequency range f>1 MHz reveals details on droplet-droplet interactions, especially in combination with the static permittivity constant [2].

We are particularly interested in a comparison between simple hydrophilic homopolymers and amphiphilic diblock copolymers in order to study possible ’anchoring effects’ of the polymers to the surfactant shell.

[1] R. Wipf et al., Colloid Polym. Sci. (2010) 288:589-601

[2] D’Angelo et al., Phys. Rev. E (1998) 58:7657-7663