%0 Journal Article
%A Wischnewski, A.
%A Monkenbusch, M.
%A Willner, L.
%A Richter, D.
%A Kali, G.
%T Direct observation of the transition from free to constrained single-segment    motion in entangled polymer melts
%J Physical review letters
%V 90
%@ 0031-9007
%C College Park, Md.
%I APS
%M PreJuSER-28406
%P 058302
%D 2003
%Z Record converted from VDB: 12.11.2012
%X We report a direct determination of the time dependent mean-squared segment displacement of a polymer chain in the melt covering the transition from free to constraint Rouse relaxation along the virtual tube of the reptation model. This has been achieved by a neutron spin-echo (NSE) measurement of the segmental self-correlation function as conveyed by the spin-incoherent scattering from two fully protonated polymer melts, polyethylene and polyethylene propylene. Within the scenario of de Gennes reptation model a transition of the time dependence of segmental mean-squared displacements from proportional tot(1/2) to proportional tot(1/4) is expected and clearly corroborated by the incoherent NSE results.
%K J (WoSType)
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000180918300062
%R 10.1103/PhysRevLett.90.058302
%U https://juser.fz-juelich.de/record/28406