Dresden 2017 – wissenschaftliches Programm
CPP 56.9: Vortrag
Donnerstag, 23. März 2017, 12:45–13:00, ZEU 260
Polymer dynamics within soft confinement — •Björn Kuttich and Bernd Stühn — Institut für Festkörperphysik, Technische Universität Darmstadt, D-64289, Germany
Microemulsions in the droplet phase are a well suited system to provide a three dimensional soft confining geometry on the length scale of several nano metres. Due to the softness of the confinement molecules which are introduced into the microemulsion droplets will change structural and dynamical properties of the confinement. In case of water in oil microemulsions stabilised by the an-ionic surfactant AOT we studied these changes for the case of the water soluble polymer poly(ethylene oxide) (PEO) enclosed in droplets of different sizes.
Furthermore, structure and dynamics of the confined polymer PEO, are investigated by small angle neutron scattering (SANS) and neutron spin echo spectroscopy (NSE). The SANS results show a significant increase of the polymer’s radius of gyration, which is related to an attractive interaction between PEO and the AOT head groups. Furthermore the internal correlations of the polymer change to that of a collapsed polymer chain.
For the NSE data the effective diffusion coefficient was investigated. On length scales larger than the droplet size pure droplet diffusion is observed. The polymer is confined to the extent of the droplet. On smaller length scales, thus at larger q values dynamics show a significantly increased effective diffusion coefficient due to the polymer dynamics.
 B. Kuttich et al., J. Chem. Phys. 145, 164904 (2016)