TY  - JOUR
AU  - Sharma, Aakash
AU  - Kruteva, Margarita
AU  - Allgaier, Jürgen
AU  - Hoffmann, Ingo
AU  - Falus, Peter
AU  - Monkenbusch, Michael
AU  - Richter, Dieter
TI  - Chain Confinement and Anomalous Diffusion in the Cross over Regime between Rouse and Reptation
JO  - ACS Macro Letters
VL  - 11
IS  - 12
SN  - 2161-1653
CY  - Washington, DC
PB  - ACS
M1  - FZJ-2022-05165
SP  - 1343 - 1348
PY  - 2022
AB  - 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.
LB  - PUB:(DE-HGF)16
C6  - 36409674
UR  - <Go to ISI:>//WOS:000889682900001
DO  - DOI:10.1021/acsmacrolett.2c00608
UR  - https://juser.fz-juelich.de/record/911918
ER  -