(550a) Evaluating Martini Forcefield Coarse-Grained Models for Polystyrene Sulfonate Polymers

Polyelectrolytes are a class of polymeric materials with a wide range of applications in materials design for energy applications¹, nanomedicine², surface coatings³, and many more. Polyelectrolytes also have relevance in molecular biology as nature uses polymeric biomacromolecules with charged components in the form of proteins, peptides, proteoglycans, DNA, RNA and more⁴. Understanding the solution behavior of polyelectrolytes is critical for the advancement of materials design using charged polymers. All atom simulations have been employed to study polyelectrolyte conformational behavior under different conditions for various polymer chemistries, however many relevant material properties of interest require system sizes that are significantly larger. Coarse-grained models for polyelectrolytes have been developed such as implicit solvent bead-spring models⁵ and explicit solvent models⁶ using the MARTINI forcefield^7-9. In this work, we seek to model the strong polyelectrolyte sodium polystyrene sulfonate (NaPSS) using a model based on the newer MARTINI v3 forcefield with nonpolarizable water beads, and a model using the older MARTNI v2 forcefield with polarizable water beads. We use these two CG models to simulate solutions of NaPSS at various polymer concentrations, salt concentrations, and degree of polymerization to evaluate the ability for each model to match radii of gyration observed in experiments¹⁰.

Works Cited

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