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Title: Dynamics in entangled polyethylene melts [Multi time scale dynamics in entangled polyethylene melts]

Polymer dynamics creates distinctive viscoelastic behavior as a result of a coupled interplay of motion at the atomic length scale and motion of the entire macromolecule. Capturing the broad time and length scales of polymeric motion however, remains a challenge. Using linear polyethylene as a model system, we probe the effects of the degree of coarse graining on polymer dynamics. Coarse-grained (CG) potentials are derived using iterative Boltzmann inversion with λ methylene groups per CG bead (denoted CGλ) with λ = 2,3,4 and 6 from a fully-atomistic polyethylene melt simulation. By rescaling time in the CG models by a factor α, the chain mobility for the atomistic and CG models match. We show that independent of the degree of coarse graining, all measured static and dynamic properties are essentially the same once the dynamic scaling factor α and a non-crossing constraint for the CG6 model are included. The speedup of the CG4 model is about 3 times that of the CG3 model and is comparable to that of the CG6 model. Furthermore, using these CG models we were able to reach times of over 500 μs, allowing us to measure a number of quantities, including the stress relaxation function, plateaumore » modulus and shear viscosity, and compare directly to experiment.« less
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [1]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
  2. Washington Univ., St. Louis, MO (United States)
  3. Clemson Univ., Clemson, SC (United States)
Publication Date:
Report Number(s):
SAND-2016-4254J
Journal ID: ISSN 1951-6355; PII: 60142; TRN: US1701553
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
European Physical Journal. Special Topics
Additional Journal Information:
Journal Volume: 225; Journal Issue: 8-9; Journal ID: ISSN 1951-6355
Publisher:
Springer
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1338912