The recently developed evolutionary algorithm USPEX proved to be a tool thatenables accurate and reliable prediction of structures for a given chemicalcomposition. Here we extend this method to predict the crystal structure ofpolymers by performing constrained evolutionary search, where each monomericunit is treated as one or several building blocks with fixed connectivity. Thisgreatly reduces the search space and allows the initial structure generationwith different sequences and packings using these blocks. The new constrainedevolutionary algorithm is successfully tested and validated on a diverse rangeof experimentally known polymers, namely polyethylene (PE), polyacetylene (PA),poly(glycolic acid) (PGA), poly(vinyl chloride) (PVC), poly(oxymethylene)(POM), poly(phenylene oxide) (PPO), and poly (p-phenylene sulfide) (PPS). Byfixing the orientation of polymeric chains, this method can be further extendedto predict all polymorphs of poly(vinylidene fluoride) (PVDF), and the complexlinear polymer crystals, such as nylon-6 and cellulose. The excellent agreementbetween predicted crystal structures and experimentally known structuresassures a major role of this approach in the efficient design of the futurepolymeric materials.
展开▼
