Journal Article

FZJ-2022-05165

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Chain Confinement and Anomalous Diffusion in the Cross over Regime between Rouse and Reptation

Sharma, A. (Corresponding author)FZJ* ; Kruteva, M. (Corresponding author)FZJ* ; Allgaier, J.FZJ* ; Hoffmann, I. ; Falus, P. ; Monkenbusch, M.FZJ* ; Richter, D.FZJ*

2022
ACS Washington, DC

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Please use a persistent id in citations: http://hdl.handle.net/2128/33673  doi:10.1021/acsmacrolett.2c00608

Abstract: By neutron spin echo (NSE) and pulsed field gradient (PFG) NMR, we study the dynamics of a polyethylene-oxide melt (PEO) with a molecular weight in the transition regime between Rouse and reptation dynamics. We analyze the data with a Rouse mode analysis allowing for reduced long wavelength Rouse modes amplitudes. For short times, subdiffusive center-of-mass mean square displacement ⟨rcom2(t)⟩ was allowed. This approach captures the NSE data well and provides accurate information on the topological constraints in a chain length regime, where the tube model is inapplicable. As predicted by reptation for the polymer ⟨rcom2(t)⟩, we experimentally found the subdiffusive regime with an exponent close to 𝜇=12, which, however, crosses over to Fickian diffusion not at the Rouse time, but at a later time, when the ⟨rcom2(t)⟩ has covered a distance related to the tube diameter.

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Contributing Institute(s):

1. Neutronenstreuung (JCNS-1)

Research Program(s):

1. 6G4 - Jülich Centre for Neutron Research (JCNS) (FZJ) (POF4-6G4) (POF4-6G4)
2. 632 - Materials – Quantum, Complex and Functional Materials (POF4-632) (POF4-632)

Appears in the scientific report 2022

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Database coverage:
; ; Chemical Reactions ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Essential Science Indicators ; IF >= 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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