Dresden 2017 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 17: Poster: Polymer Networks and Dynamics
CPP 17.6: Poster
Montag, 20. März 2017, 18:30–21:00, P1C
Topological interactions in polymers under shear — Maciej Kawecki1, Franz Adlmann1, Philipp Gutfreund2, Sudipta Gupta3, Peter Falus2, David Uhrig3, and •Max Wolff1 — 1Department for Physics and Astronomy, Uppsala Univeristy, Sweden — 2Institut Laue-Langevin, Grenoble, France — 3Oak Ridge National Laboratory, Oak Ridge, TN, USA
Since decades topological interactions as described by the reptation theory of DeGennes, Doi and Edwards are among the most successful concepts in physics. The scaling laws and viscoelastic properties in polymers are predicted correctly. However, currently no such generalized theory is available for large deformations, where shear thinning occurs. Even more, until now, no experimental approach allowed to test possible extensions of the reptation theory, such as convective constrain release, which would have the potential to theoretically predict the shear thinning transition. We present a neutron spin echo based method to directly measure and quantify nanoscale dynamics in flowing liquids and we extract the chain dynamics in a polymeric melt beyond the shear thinning transition. Under flow we find an additional relaxation process, which we attribute to shear thinning and which is in line with the theory of convective constrain release.