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    A reactive coarse-grained model capable of step-growth polymerization is proposed.
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    The resulting linear polymer chains follow the Flory-Schulz distribution.
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    Both chemical reaction and polydispersity affect diffusion of polymer melts.
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    Both strain rate and polydispersity affect mechanical response of polymer glass.

Abstract

Most existing particle-based polymeric models are non-reactive, and usually constructed to be monodisperse. This deficiency limits the utilization of these models to understand the dependency of polymer properties on polydispersity. Here we report a coarse-grained model with pairwise interactions, yet is reactive and capable of in silico synthesis of polydisperse polymers in a step-wise manner. The polymerization of linear, branched, cross-linked and network polymers can be described by this reactive model. The chain length distribution of the resulting linear polymer agrees well with the Flory-Schulz distribution. The importance of polydispersity in polymer behaviors is highlighted in terms of kinetic (self-diffusivities of linear polymer melts) and mechanical properties (stress-strain responses of linear polymer glasses under uniaxial tension).

Graphical abstract

Keywords

  • Molecular dynamics
  • Reactive force field
  • Polydispersity