STUDY OF THE DEPENDENCE OF THE THERMAL CONDUCTIVITY OF A SINGLE POLYETHYLENE CHAIN ON LENGTH, TEMPERATURE, AND MECHANICAL STRAIN USING MOLECULAR DYNAMICS SIMULATIONS

摘要

Although bulk polyethylene, as a thermal insulator, has an extremely low thermal conductivity, an individual polyethylene chain showed a very high thermal conductivity. Exploring the thermal transport in a single polyethylene chain is significant for broadening application of polymers with better thermal properties. In this paper, we numerically investigate the thermal conductivity of an individual polyethylene chain by the Green-Kubo approach. We report the dependence of its thermal conductivity upon length, temperature, and mechanical strain, respectively. The results suggest that the thermal conductivity of an individual polyethylene chain depends greatly on the temperature and shows an interesting trend over the length under different temperatures. The influence of the temperature on the convergence of the thermal conductivity is also studied here. Moreover, the mechanical strain is observed to improve the thermal conductivity significantly. The thermal conductivity increases with the mechanical strain. The power spectra are used to analyze the phonon properties at different temperatures and mechanical strains. This study could guide the development of advanced high-thermal-conductivity polymers and polymer-based nanocomposites.