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Title: Polymer Topology Effects on Dynamics of Comb Polymer Melts

Abstract

Controlling polymer viscosity and flow is key to their many applications through strength and processability. The topology of the polymer i.e., linear, stars, and branched, affects the macroscopic flow characteristics of melts, where introducing one branch is sufficient to increase the viscosity significantly. While a number of studies have probed the effects of polymer topology on their rheology, the molecular understanding that underlies the macroscopic behavior remains an open question. The current study uses molecular dynamics simulations to resolve the effects of topology of polymer melts on chain mobility and viscosity in the comb regime using polyethylene as a model system. A coarse-grained model where four methylene groups constitute one bead is used, and the results are transposed to the atomistic level. Here, we find that while the number of branches only slightly affects the chain mobility and viscosity, their length strongly impacts their behavior. Finally, the results are discussed in terms of interplay between the relaxation of the branches and reptation of the backbone where the topology of the polymer affects the tube dimensions.

Authors:
 [1]; ORCiD logo [1]; ORCiD logo [2]
  1. Clemson Univ., SC (United States). Dept. of Chemistry
  2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1474056
Alternate Identifier(s):
OSTI ID: 1477311
Report Number(s):
SAND-2018-10129J; SAND2018-10461J
Journal ID: ISSN 0024-9297; 667902
Grant/Contract Number:  
AC04-94AL85000; NA0003525
Resource Type:
Accepted Manuscript
Journal Name:
Macromolecules
Additional Journal Information:
Journal Volume: 51; Journal Issue: 19; Journal ID: ISSN 0024-9297
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Wijesinghe, Sidath, Perahia, Dvora, and Grest, Gary S. Polymer Topology Effects on Dynamics of Comb Polymer Melts. United States: N. p., 2018. Web. https://doi.org/10.1021/acs.macromol.8b01449.
Wijesinghe, Sidath, Perahia, Dvora, & Grest, Gary S. Polymer Topology Effects on Dynamics of Comb Polymer Melts. United States. https://doi.org/10.1021/acs.macromol.8b01449
Wijesinghe, Sidath, Perahia, Dvora, and Grest, Gary S. Thu . "Polymer Topology Effects on Dynamics of Comb Polymer Melts". United States. https://doi.org/10.1021/acs.macromol.8b01449. https://www.osti.gov/servlets/purl/1474056.
@article{osti_1474056,
title = {Polymer Topology Effects on Dynamics of Comb Polymer Melts},
author = {Wijesinghe, Sidath and Perahia, Dvora and Grest, Gary S.},
abstractNote = {Controlling polymer viscosity and flow is key to their many applications through strength and processability. The topology of the polymer i.e., linear, stars, and branched, affects the macroscopic flow characteristics of melts, where introducing one branch is sufficient to increase the viscosity significantly. While a number of studies have probed the effects of polymer topology on their rheology, the molecular understanding that underlies the macroscopic behavior remains an open question. The current study uses molecular dynamics simulations to resolve the effects of topology of polymer melts on chain mobility and viscosity in the comb regime using polyethylene as a model system. A coarse-grained model where four methylene groups constitute one bead is used, and the results are transposed to the atomistic level. Here, we find that while the number of branches only slightly affects the chain mobility and viscosity, their length strongly impacts their behavior. Finally, the results are discussed in terms of interplay between the relaxation of the branches and reptation of the backbone where the topology of the polymer affects the tube dimensions.},
doi = {10.1021/acs.macromol.8b01449},
journal = {Macromolecules},
number = 19,
volume = 51,
place = {United States},
year = {2018},
month = {9}
}

Journal Article:
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Cited by: 2 works
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Figures / Tables:

Figure 1 Figure 1: Snapshots of CG chains of polyethylene with backbone of $n$ = 480 carbons (120 CG beads) with (a) no side chains, (b) $n$b = 4 branches of length $n$s= 40 carbon atoms (10 CG beads) and (c) $n$b= 8 branches of length $n$s= 80 carbon atoms (20 CGmore » beads). Backbone beads are purple and side chain beads are green.« less

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Works referenced in this record:

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    • DOI: 10.1002/adma.201806484

    Coarse-graining auto-encoders for molecular dynamics
    journal, December 2019