Polymer interactions with additive


I’m trying to model polymer-additive interactions through coarse-grained modeling. Currently I have a long chain polymer system setup with additives only being single beads. I’ve been playing around with the Lennard-Jones potential, especially the sigma parameter for the polymer-additive interaction.

What is a better approach to have the additive “like” the polymer system more than itself, while also lowering glass transition temperature (Tg). Increasing the sigma value does lower the Tg, but when sigma is too large the system would break - then I moved to looking at:

pair_style hybrid/overlay lj soft
pair_style lj/cut/soft

But with so many more parameters to consider, it becomes hard to control.

Any help would be appreciated.

Thank you,

This is a question about your model, not really about LAMMPS.

I suggest you look in the literature to see how others have

modeled this kind of CG system.