2000/08/24 by T. Kreer, J. Baschnagel, M. Mueller +3 · 1 citation
Chemical Engineering · Engineering · Materials Science · Physics and Astronomy · #Material Dynamics and Properties #Phase Equilibria and Thermodynamics #Rheology and Fluid Dynamics Studies #cond-mat.dis-nn #cond-mat.soft
paper · pdf · doi:10.1021/ma001500f
38 pages of REVTeX, 14 PostScript figures
arxiv created 2000/08/24 · openalex publication_date 2001/01/20 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present data from Monte Carlo simulations for monodisperse linear polymer chains in dense melts with degrees of polymerization between N = 16 and N = 512. The aim of this study is to investigate the crossover from Rouse-like dynamics for short chains to reptation-like dynamics for long chains. To address this problem, we calculate a variety of different quantities: standard mean-square displacements of inner monomers and of the chain's center of mass, the recently proposed cubic invariant (Ebert, U.; et al. Phys. Rev. Lett. 1997, 78, 1592), persistence of bond-vector orientation with time, and the autocorrelation functions of the bond vector, the end-to-end vector, and the Rouse modes. This analysis reveals that the crossover from nonentangled to entangled dynamics is very protracted. Even the biggest chain length N = 512, which is about 14 times larger than the entanglement length, shows no clear evidence for reptation. In the opposite limit of short chains, no pure Rouse behavior is found either. Local stiffness effects have to be taken into account.