Atomistically-informed coarse-grained molecular dynamics simulations of blends of polysulfamides

Polysulfamides are a new class of polymers with the potential to serve as sustainable alternatives to commodity plastics. Our collaborators [ ACS Polymers Au 2023,3,3,259-266] have synthesized polysulfamides and demonstrated their high thermal stability, tunable glass transition temperatures, and eco-friendly degradability. They [Macromolecules 2023, 56, 13, 5033–5049] find that H-bonding between sulfamides causes chains to assemble into structures with varying crystallinity; the extent of crystallinity is affected by the choice of segments along the chain backbone. To understand how the choice of segments along the backbone affects the assembled structure, we develop an atomistically-informed coarse-grained (CG) model of polysulfamide. Atomistic simulations quantify hydrogen donor and acceptor placement in the sulfamide CG bead and angle/dihedral distributions along the chains. Using CG molecular dynamics (MD) simulations we find that increasing bulkiness of the segments on either side of the sulfamide group hinders crystallization and decreasing segments’ contour lengths enhances crystallization. We extend this CG MD simulation study to blends of polysulfamides with varying chain designs (e.g., H-bonding frequency and segment sizes) to characterize the extent of H-bonding, blend miscibility, and the assembled structure.