Dynamics of polymers in elongational flow investigated by inelastic neutron scattering


Abstract in English

The nanoscale fluctuation dynamics of semi dilute high molecular weight polymer solutions of Polyethylenoxide (PEO) in D2O under non-equilibrium flow conditions were studied by the neutron spin-echo technique. The sample cell was in contraction flow geometry and provided a pressure driven flow with a high elongational component that stretched the polymers most efficiently. The experiments suggest that the mobility on the scale of a few monomers, comparable to the Kuhn segment length, becomes highly anisotropic and is enhanced perpendicular to the flow direction. Diffraction data show a weak structural correlation along the chains on a length scale of about 17 Angstroems, which might be related to the Kuhn length in this system.

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