TY - GEN
T1 - Atomistic details of disordering processes in superheated polymethylene crystals II. Effects of surface constraints
AU - Wunderlich, B.
AU - Liang, G. L.
AU - Sumpter, B. G.
AU - Noid, D. W.
PY - 1994
Y1 - 1994
N2 - Atomistic details of disordering in superheated polymethylene crystals have been studied using full molecular dynamics simulations of crystals containing 9600 CH2-groups. The crystal size was about 227 nm3. Simulations were carried out for up to 100 ps, starting at temperatures about 100 K above the melting temperature. Typically 1.5 h of CPU time on a Cray X-MP were necessary per ps simulation. Superheating causes a quick development of large-scale disorder throughout the crystal, including reorientation, translation, and the destruction of crystal symmetry. This is followed ultimately by surface melting. Crystallization centers with hexagonal packing are found in superheated, unconstrained crystals. On cooling during the simulation, recrystallization processes compete with the disordering, resulting in a reorientation of the molecular chains and reorganization of the crystal. Neither the fully amorphous phase nor the ordered crystal are reached during these short-time simulations using an instantaneous temperature increase to above the melting temperature, followed by a slow cooling into the crystallization temperature region.
AB - Atomistic details of disordering in superheated polymethylene crystals have been studied using full molecular dynamics simulations of crystals containing 9600 CH2-groups. The crystal size was about 227 nm3. Simulations were carried out for up to 100 ps, starting at temperatures about 100 K above the melting temperature. Typically 1.5 h of CPU time on a Cray X-MP were necessary per ps simulation. Superheating causes a quick development of large-scale disorder throughout the crystal, including reorientation, translation, and the destruction of crystal symmetry. This is followed ultimately by surface melting. Crystallization centers with hexagonal packing are found in superheated, unconstrained crystals. On cooling during the simulation, recrystallization processes compete with the disordering, resulting in a reorientation of the molecular chains and reorganization of the crystal. Neither the fully amorphous phase nor the ordered crystal are reached during these short-time simulations using an instantaneous temperature increase to above the melting temperature, followed by a slow cooling into the crystallization temperature region.
UR - http://www.scopus.com/inward/record.url?scp=0028274499&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:0028274499
SN - 1558992200
T3 - Materials Research Society Symposium Proceedings
SP - 93
EP - 98
BT - Crystallization and Related Phenomena in Amorphous Materials
A2 - Libera, Matthew
A2 - Haynes, Tony E.
A2 - Cebe, Peggy
A2 - Dickinson Jr., James E.
PB - Publ by Materials Research Society
T2 - Proceedings of the 1993 Fall Meeting of the Materials Research Society
Y2 - 29 November 1993 through 2 December 1993
ER -