Uncrossability constraints in mesoscopic polymer melt simulations: Non-Rouse behavior of C120H242

Abstract

Effects of alignment layer thickness on the pretilt angle of liquid crystals APL: Org. Electron. Photonics 3, 270 (2010) Effects of alignment layer thickness on the pretilt angle of liquid crystals Appl. Phys. Lett. 97, 243306 (2010) Field-theoretic model of inhomogeneous supramolecular polymer networks and gels J. Chem. Phys. 133, 174903 (2010) Origin of translocation barriers for polyelectrolyte chains JCP: BioChem. Phys. 3, 11B610 (2009) Origin of translocation barriers for polyelectrolyte chains J. Chem. Phys. 131, 194903 (2009) Additional information on J. Chem. Phys. An important feature of a melt of long polymers is that the bonds of the chains cannot cross each other. This seemingly simple fact has a great impact on the long time dynamics and rheology of the material. In this paper an algorithm is described that explicitly detects and prevents bond crossings in mesoscopic simulations of polymers. The central idea is to view the bonds as slippery elastic bands which can become entangled. The method is applied to a simulation of a coarse-grained melt of C 120 H 242 , in which each chain is represented by six blobs. The long time dynamics and zero-shear rate rheology are investigated and the relative importance of uncrossability and chain stiffness is established. As a result of the uncrossability of the chains, we observe a subdiffusive exponent in the mean square displacement of the chains, a stretching of the exponential decay of the Rouse mode relaxations, an increase of relaxation times associated with large scales, and a slowing down of the relaxation of the dynamic structure factor. These results are in agreement with results from previous microscopic molecular dynamics simulations. Finally, an increased viscosity as compared to the Rouse model is observed, which is attributed to slowly decaying interchain stress components.

Energy Landscape and Isotropic Tensile Strength of n-Alkane Glasses

“…Their work suggests that chains of length greater than n ) 8 should contain topological interchain entanglements, even though they might not exhibit rheological entanglement dynamics. Although the topological problem of identifying chain entanglements at the atomistic level remains unsolved, 37,[80][81][82][83][84][85][86] visual inspection of the configurations for the longer chains, n ) 16, 24, and 48, confirms that the molecules tend to adopt curled or folded conformations and tend to intertwine, indicating there is some degree of entanglement present. However, results from the landscape equations of state and the deformation curves show a counterintuitive trend, namely that the tensile strength decreases with chain length beyond n ) 3.…”

Microscopic Description of Entanglements in Polyethylene Networks and Melts: Strong, Weak, Pairwise, and Collective Attributes

“…However, upon nonlinear deformation or flow, LLS could possibly act as a CR mechanism. A similar mechanism was implemented 95,110,111 by Padding and Briels to enforce chain uncrossability in a coarse grained model of polyethylene.…”

Resolving Dynamic Properties of Polymers through Coarse-Grained Computational Studies

“…Polyethylene chains have previously been studied using CG models with beads of λ = 3 − 48 methylene groups per bead [14][15][16][17][18][19]. These studies were able to capture the radius of gyration as a function of molecular weight and the pair correlation function between CG beads.…”