BUILDING LARGE AMORPHOUS POLYMER STRUCTURES - ATOMISTIC SIMULATION OFGLASSY POLYSTYRENE

A technique is presented for generating atomistic models of amorphous polymer structures starting from chain configurations on lattice. The method guarantees Gaussian chain statistics and enables control of cha in tacticity and monomer sequence while avoiding severe overlaps betwe en the atoms in the structure. We show that the single polymer chain, which completely occupies the lattice with periodic boundary condition s, is Gaussian with chain statistics equivalent to that obtained for a nonreversing random walk on the cubic lattice. The method enables eff icient generation of the chain topology, which can then be populated w ith specific chemical units. Large models of glassy, atactic polystyre ne have been generated, and the effects of system size are examined in terms of calculated X-ray scattering intensities. These results demon strate the efficacy of this new method for generating more realistic p olymer glass structures.