Thermomechanically Consistent and Temperature Transferable Coarse-Graining of Atactic Polystyrene

We present a systematic, two-bead per monomer coarse-graining strategy allowing for the prediction of the thermomechanical behavior of polystyrene. Analytical bonded potentials optimized to match atomistic bonded distributions for different stereochemistries emulate local structure. Alternatively, the backbone torsional potential is leveraged to match the chain stiffness in a direct approach. Nonbonded potentials using a temperature-dependent density correction term demonstrate transferability of the temperature-dependent modulus. Flory–Fox constants of the T g-optimized CG model are commensurate with all-atomistic and experimental results. The thermomechanically consistent coarse-graining (TCCG) procedure is demonstrated using polystyrene as a benchmark system to be a robust and effective technique to extend the computational prediction of the thermomechanical behavior of polymers to the mesoscale.