Nonequlibrium molecular dynamics (NEMD) has been used to simulate the heat transport in single PE chains stretched along the main chain direction.The effects of chain length (L) and tensile strain () on thermal conductivity of single PE chains are investigated.Furthermore

the microscopic mechanism of heat transport in polymer chains is studied.The simulation results show that the thermal conductivity of PE increases with increasing L and

and the trend gets gently.This trend about L is understood to be a result of competition between ballistic phonon transport and diffusive phonon transport in a single polymer chain and limitation from the finite-size effects.The trend about is determined by the growing phonon mean free path and decreasing number density of atoms during drawing.The spectrum of vibrational density of states (VDOS) presents some high frequency peaks which represent different vibrations (stretching

bending

etc.) in PE chains

and these high vibrations decrease with increasing .The low frequency peaks of spectrum of VDOS associated with low frequency modes of vibrations are strengthened at first and then weakened with increasing

known to be significant for thermal conduction due to their thermal diffusivity.