Towards In Situ Studies of Polymer Dynamics and Entanglement under Shear through Neutron Spin Echo Spectroscopy

Entangled polymeric fluids subjected to shear display a stress plateau through a range of shear rates. The formation of this plateau is often attributed to an entanglement-disentanglement transition in scientific literature. However, to our best knowledge in situ studies recovering the intermediate...

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Bibliographic Details
Main Author: Kawecki, Maciej
Format: Others
Language:English
Published: Uppsala universitet, Materialfysik 2015
Subjects:
NSE
Online Access:http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-262370
Description
Summary:Entangled polymeric fluids subjected to shear display a stress plateau through a range of shear rates. The formation of this plateau is often attributed to an entanglement-disentanglement transition in scientific literature. However, to our best knowledge in situ studies recovering the intermediate scattering function of polymer dynamics under shear have until now never been performed. This thesis documents the successful development of a high viscosity shear device whose interaction with polarized neutrons is small enough to allow use for Neutron Spin Echo spectroscopy. Further, first measurements towards the direct observation of the variation of the degree of entanglement throughout increasing shear are documented, albeit yet for too short Fourier times to measure beyond Rouse dynamics.