Assessment of an Anisotropic Coarse-Grained Model for Cis-Polybutadiene Obtained by a Bottom-up Approach

As it has been shown in previous coarse-grained simulations of polymer systems, the spherical representation utilized for the coarse-grained beads cannot capture anisotropic effects that play a crucial role on the structural features as well as on the dynamic response of such systems [1-2].
On these grounds, the aim of this study is to extract a coarse-grained potential for cis-polybutadiene in the melt state by taking into account the shape of the polymer beads. A conservative potential depending on the distance and the relative orientation of the polymer beads is deduced from atomistic molecular dynamics (MD) simulations.The translational dynamics of the beads is tracked using the position and momentum of their center-of-mass, whereas their rotational dynamics is modeled by representing their orientation through the use of quaternions. The efficacy of this approach to reproduce static features of the polymer melt is assessed in coarse-grained simulations and is also compared with respective isotropic models.

References

[1] Srivastra A., Ghosh S., Phys. Rev. E, 2012, 85, 026702−026712.
[2] Poier P. ; Likos C.N. , Moreno A.J. , Blaak R., Macromolecules, 2015, 48, 4983-4997.