ATOMISTIC DETAILS OF DISORDERING PROCESSES IN SUPERHEATED POLYMETHYLENE CRYSTALS

Atomistic details of disordering in superheated polymethylene crystals have been studied using molecular dynamics simulations. Superheating causes a quick development of large-scale disorder throughout the crystal, including reorientation, translation, and the destruction of crystal symmetry, followed ultimately by surface melting. Crystallization-centers with hexagonal packing are found in the superheated, unconstrained crystals. On cooling during the simulation, a recrystallization process competes with the disordering resulting in a reorientation of the molecular chains and reorganization of the crystal. ''The submitted manuscript has been authored by a contractor of the U.S. Government under contract No. DE-AC05-84OR-21400. Accordingly, the U.S. Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for U.S. Government purposes.''