Regensburg 2016 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 57: Polymer Dynamics and Rheology (joint session CPP/DY, organized by CPP)
CPP 57.10: Vortrag
Donnerstag, 10. März 2016, 17:30–17:45, H40
Disentanglement of polymers under shear — Maciej Kawecki1, Philipp Gutfreund2, Franz Adlmann1, Stephane Longeville3, Alain Lapp3, Piotr Zolnieczuk4, Peter Falus2, and •Max Wolff1 — 1Department for Physics and Astronomy, Uppsala University, Sweden — 2Institut Laue-Langevin, Grenoble, France — 3Institut Leon Brillouin, Scala, France — 4Oak Ridge National Laboratory, Oak Ridge, USA
Neutron Spin Echo spectroscopy provides unique insight into molecular and sub-molecular dynamics in soft matter. In polymer physics a stress plateau is observed for increasing shear rate, which might be explained by an entanglement-disentanglement transition and change the dynamics of the chains drastically. Neutron Spin Echo provides information about entanglement length and degree by probing the local dynamics of the polymer chains. Combining shear experiments and neutron spin echo is challenging since, first the beam polarisation has to be preserved during scattering and second, Doppler scattered neutrons may cause inelastic scattering. We demonstrate that a high beam polarisation can be preserved and present SANS data revealing shear- induced conformational changes in highly entangled polymers as well as Spin Echo measurements indicating an disentanglement transition under shear.