An Iterative Method for Producing Equilibrated Symmetric Three‐Arm Star Polymer Melts in Molecular Dynamics

Abstract

Melts of symmetric three‐arm stars are generated using a novel iterative method. In this method, an equilibrated low molecular weight configuration is used to generate progressively higher molecular weights by affine scaling and equilibration. At each stage in the progression, the synthetically lowered entanglement density allows bypassing of the exponentially large relaxation times of branched polymers. The quality of equilibration was assessed by measuring the mean dimensions, distribution of dimensions, and internal length scales of the polymers. The total time required to generate the progression of equilibrated configurations was seen to scale as the Rouse time of the highest molecular weight. magnified image

Understanding and Modeling Polymers: The Challenge of Multiple Scales

“…An interesting application of multiresolution tools is the generation of equilibrated polymer melt configurations for large molecular weightwhich is still a difficult problem in polymer simulations . In traditional approaches, one first prepares a reasonably random initial configuration, e.g., by assembling a number of polymers with typical melt configurations, and then further relaxes it by implementing unphysical dynamics and/or Monte Carlo moves that allow chain crossing or even change chain connectivity. − In multiscale approaches, − one uses CG simulations to equilibrate the melt and then reconstructs a FG configuration by increasing the level of resolution in a stepwise fashion. Tubiana et al have recently performed a systematic comparison of a traditional and a multiscale equilibration scheme, focusing on topological indicators such as knot distributions, and found excellent agreement …”

Parallel Replica Dynamics of Bead‐Spring Elastomers at Low Strain Rates

“…Note that the dephasing time chosen was arbitrary. The results obtained with this smaller dephasing time were spot checked by increasing the dephasing time to t = 10 4 τ, which is the Rouse time (or segment relaxation time) of the chains in the bead‐spring polymer model . The results obtained from the two different dephasing times were identical.…”

Computational Software: Polymer Chain Generation for Coarse-Grained Models Using Radical-Like Polymerization

“…Coarse-grained molecular dynamics is a well-adapted tool for studying the mechanical behavior of polymers [1,2]. It is widely used for studying various mechanical properties (elastic constants [3,4], strain hardening [5], failure [6,7], etc) for various polymer structures (linear chains [8,9], cross-linked chains [10], branched polymers [11,12], co-polymers [13,14], gels [15]). To create these structures, several methods have been developed.…”

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