title: Do deviations from reptation scaling of entangled polymer melts result from single- or many-chain effects?
abstract: By studying the relaxation of small amounts of short entangled "probe" chains in a high molecular weight matrix, we show that the deviations from reptation scaling of the longest relaxation time are not as much dominated by single-chain effects (usually referred to as contour length fluctuations or CLF) as assumed by current mesoscopic models but also originate to a very significant extent from mutual chain relaxation effects. This result is in fact consistent with literature data on tracer and self-diffusion. Moreover, tube theories also overpredict the influence of CLF on the plateau modulus. Improved theories, simulations, and careful experiments are urgently needed to resolve this important question.
authors.affiliation: Unité de Chimie et de Physique des Hauts Polymères, Université Catholique de Louvain, B-1348 Louvain-La-Neuve, Belgium.
authors.forename: Chen-Yang
authors.initials: CY
authors.lastname: Liu
authors.forename: Roland
authors.initials: R
authors.lastname: Keunings
authors.forename: Christian
authors.initials: C
authors.lastname: Bailly