Dresden 2006 – scientific programme

Parts | Days | Selection | Search | Downloads | Help

CPP: Chemische Physik und Polymerphysik

CPP 11: POSTER Disperse Polymer Systems

CPP 11.39: Poster

Tuesday, March 28, 2006, 17:00–19:00, P3

Polymer-Induced Transient Networks in Water-in-Oil Microemulsions Studied by Dynamic Light Scattering — •Thomas Blochowicz, Christoph Gögelein, and Bernd Stühn — Institute of Solid State Physics, TU-Darmstadt, 64289 Darmstadt

We study water-in-oil microemulsions, i.e. dispersions of water droplets coated with a monolayer of surfactant in a continuous oil phase. Of particular interest for the present work is the system consisting of water, n-decane and the anionic surfactant AOT. On addition of the amphiphilic triblock copolymer PEO(polyethylenoxide)-PI(polyisoprene)-PEO a transient network is formed. The dynamics of concentration fluctuations consisting of the translational diffusion of the droplets and the relaxation of the network are monitored with photon correlation spectroscopy. We mainly focus on the variation of the dynamic behavior as a function of two different parameters, namely the number of polymer molecules per droplet Z and the droplet volume fraction φ, which can be taken as a measure for the inter droplet distance. With increasing polymer content the dynamics of the system slows down and three different relaxation processes may be distinguished. We discuss the origin of the different relaxation modes. In particular it turns out that the intermediate relaxation mode may be suppressed by index matching the oil matrix and the PI block and that the network formation sensitively depends on the interdroplet distance.