Characterizing solutions of long polymer chains by molecular dynamics (MD) simulations with quantitative force fields is a significant computational challenge. Modern MD software can treat systems large enough to accommodate realistic chain lengths (up to 100 nanometers), but the time scales needed to cover the equilibrium ensemble remain largely inaccessible. Building on previous work, we introduce protocols for parallel-tempering simulations driven by geometric selection criteria. Configurations are sampled by iterative changes in the molecular connectivity, using protocols implemented in the LAMMPS software. Benchmark simulations of liquid-crystalline polymers show that the computational overhead is minimal, and the increase in relaxation rates greatly outweighs the cost of using multiple replicas.

Enhanced sampling of polymer solutions by molecular-dynamics simulation: implementation and use cases

256th National Meeting (2018)

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