Thermal Transport in Polyethylene: The Effect of Force Fields and Crystallinity
Sandra Sæther, Merete Falck, Zhiliang Zhang, Anders Lervik, Jianying He
Abstract
In this article, we study the local structure and heat transfer properties (thermal conductivity and interfacial conductance) in model semi-crystalline Polyethylene (PE) by non-equilibrium molecular dynamics. We compare three different force fields with different level of detail (all-atom, all-atom with constraints, and united-atom), and find that the structure of the model PE is significantly influenced by the choice of force field. The united-atom force field results in a reduced overall crystallinity and an over- idealized organization of the polymer chains, compared to the all-atom force fields. We find that thermal transport properties are not greatly influenced when structural effects are taken into consideration, and our results suggest that united-atom models can be used to study heat transfer properties of model PE, with decreased computational cost.