Deformation-induced accelerated dynamics in polymer glasses

Journal Article · Thu Oct 28 04:00:00 EDT 2010 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.3505149· OSTI ID:21559941

Warren, Mya ^[1]; Rottler, Joerg ^[2]

---

1. Center for Theoretical Biological Physics, University of California at San Diego, La Jolla, California 92093 (United States)
2. Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1 (Canada)

Molecular dynamics simulations are used to investigate the effects of deformation on the segmental dynamics in an aging polymer glass. Individual particle trajectories are decomposed into a series of discontinuous hops, from which we obtain the full distribution of relaxation times and displacements under three deformation protocols: step stress (creep), step strain, and constant strain rate deformation. As in experiments, the dynamics can be accelerated by several orders of magnitude during deformation, and the history dependence is entirely erased during yield (mechanical rejuvenation). Aging can be explained as a result of the long tails in the relaxation time distribution of the glass, and similarly, mechanical rejuvenation is understood through the observed narrowing of this distribution during yield. Although the relaxation time distributions under deformation are highly protocol specific, in each case they may be described by a universal acceleration factor that depends only on the strain.

• OSTI ID: 21559941
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 16 Vol. 133; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ACCELERATION
AGING
CALCULATION METHODS
CREEP
DEFORMATION
DISTRIBUTION
GLASS
MECHANICAL PROPERTIES
MOLECULAR DYNAMICS METHOD
PARTICLES
POLYMERS
RELAXATION
RELAXATION TIME
SIMULATION
STRAIN AGING
STRAIN RATE
STRAINS
STRESSES
TRAJECTORIES
YIELDS