Molecular dynamics simulation of chains mobility in polyethylene crystal
  The mobility of polymer chains in perfect polyethylene (PE) crystal was calculated as a function of temperature and chain length through Molecular dynamics (MD) in united atom approximation. The results demonstrate that the chain mobility drastically increases in the vicinity of the phase transition from the orthorhombic to quasi-hexagonal phase. In the quasi-hexagonal phase, the chain mobility is almost independent on temperature and inversely proportional to the chain length. 
V. I. Sultanov, V. V. Atrazhev, D. V. Dmitriev, S. F. Burlatsky
cond-mat.soft