Conformationally averaged iterative Brownian dynamics simulations of semidilute polymer solutions.

Bibliographic Details
Title: Conformationally averaged iterative Brownian dynamics simulations of semidilute polymer solutions.
Authors: Young, Charles D.1, Marvin, Michael2, Sing, Charles E.1 cesing@illinois.edu
Source: Journal of Chemical Physics. 11/7/2018, Vol. 149 Issue 17, pN.PAG-N.PAG. 13p. 1 Diagram, 8 Graphs.
Subject Terms: *POLYMER solutions, *MOLECULAR conformation, *DIFFUSION tensor imaging, *CHEMICAL equilibrium, *SIMULATION methods & models
Abstract: The dynamics of semidilute polymer solutions are important to many polymer solution processing techniques such as fiber spinning and solution printing. The out-of-equilibrium molecular conformations resulting from processing flows directly impact material properties. Brownian dynamics (BD) simulations are a standard technique for studying this connection between polymer conformations in solution and processing flows because they can capture molecular-level polymer dynamics. However, BD simulations of semidilute polymer solutions are computationally limited by the calculation of hydrodynamic interactions (HIs) via an Ewald summed diffusion tensor and stochastic Brownian displacements via the decomposition of the diffusion tensor. Techniques based on the Cholesky decomposition scale with the number of particles N as O(N3) and approximations in the literature have reduced this scaling to as low as O(N). These methods still require continuous updating of the diffusion tensor and Brownian displacements, resulting in a significant constant per-time step cost. Previously, we introduced a method that avoids this cost for dilute polymer solutions by iterative conformational averaging (CA) of intramolecular HIs. In this work, we extend the CA method to semidilute solutions by introducing a grid-space average of intermolecular HIs and a pairwise approximation to the Brownian displacements based on the truncated expansion ansatz of Geyer and Winter. We evaluate our method by first comparing the computational cost with that of other simulation techniques. We verify our approximations by comparison with expected results for static and dynamic properties at equilibrium and use our method to demonstrate the concentration dependence of HI screening. [ABSTRACT FROM AUTHOR]
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Database: Academic Search Complete
More Details
ISSN:00219606
DOI:10.1063/1.5041453
Published in:Journal of Chemical Physics
Language:English