Massively Parallel Simulations of Diffusion in Dense Polymeric Structures

An original technique to generate close-to-equilibrium dense polymeric structures is proposed. Diffusion of small gases is studied on the equilibrated structures using massively parallel molecular dynamics simulations running on the Intel Teraflops (9200 Pentium Pro processors) and Intel Paragon (1840 processors). Compared to the current state-of-the-art equilibration methods the new technique is faster by some orders of magnitude. The main advantage of the technique is that one can circumvent the bottlenecks in configuration space that inhibit relaxation in molecular dynamics simulations. In agreement with experimental evidence, small gas diffusion coefficients are larger for ethylene-propylene-dimer-monomer (EPDM) than butyl rubber.