Scientific Publications of Jos Aerts

Summary

A method is presented for the fast prediction of polymer crystal structures. From a stable helical conformation of the polymer chain well packed three dimensional periodic starting structures are generated using an adapted version of M.Blanco's Molecular Silverware algorithm. These structures are then energy-minimised using classical molecular mechanics methods. The method only requires a rough estimate of the crystalline density. No information about crystal class, space group or cell parameters is necessary. Using these method, possible crystal structures of poly(ethylene ketone), Nylon-6,6 and poly(ethylene terephthalate) are calculated. Both the alfa- and beta-structures of poly(ethylene ketone) are correctly predicted. For Nylon-6,6 the lowest-energy structure obtained corresponds to the experimental alfa-structure. For poly(ethylene terephthalate) a large number of structures are generated using the algorithm. Besides the experimental structure four structures are found with a lower energy than the experimental structure.