Detailed analysis of Rouse mode and dynamic scattering function of highly entangled polymer melts in equilibrium

Abstract

We present large-scale molecular dynamics simulations for a coarse-grained model of polymer melts in equilibrium. From detailed Rouse mode analysis we show that the time-dependent relaxation of the autocorrelation function (ACF) of modes $p$ can be well described by the effective stretched exponential function due to the crossover from Rouse to reptation regime. The ACF is independent of chain sizes $N$ for $N/p<N_e$ ($N_e$ is the entanglement length), and there exists a minimum of the stretching exponent as $N/p\to N_e$. As $N/p$ increases, we verify the crossover scaling behavior of the effective relaxation time ${\tau }_{\mathrm{eff},p}$ from the Rouse regime to the reptation regime. We have also provided evidence that the incoherent dynamic scattering function follows the same crossover scaling behavior of the mean square displacement of monomers at the corresponding characteristic time scales. The decay of the coherent dynamic scattering function is slowed down and a plateau develops as chain sizes increase at the intermediate time and wave length scales. The tube diameter extracted from the coherent dynamic scattering function is equivalent to the previous estimate from the mean square displacement of monomers.

8 pages, 7 figures, to be published in EPJST special issue on "Phase transitions and critical phenomena" (2017)

References in corpus (2)

• Static and dynamic properties of large polymer melts in equilibrium
• Equilibration of High Molecular-Weight Polymer Melts: A Hierarchical Strategy

Cited by in corpus (10)

• Clustering of entanglement points in highly strained polymer melts
• Chain retraction in highly entangled stretched polymer melts
• Elongational viscosity of weakly entangled polymer melt via coarse-grained molecular dynamics simulation
• Efficient equilibration of confined and free-standing films of highly entangled polymer melts
• Effects of chain length on Rouse modes and non-Gaussianity in linear and ring polymer melts
• Relaxation Dynamics of Entangled Linear Polymer Melts via Molecular Dynamics Simulations
• Dynamics and Stress Relaxation of Bidisperse Polymer Melts with Unentangled and Moderately Entangled Chains
• Unraveling the glass-like dynamic heterogeneity in ring polymer melts: From semi-flexible to stiff chain
• Dynamical structure of entangled polymers simulated under shear flow
• 5D Entanglement in Star Polymer Dynamics