Order-disorder transitions and melting in a helical polymer crystal: molecular dynamics calculations of model poly(ethylene oxide)

Abstract

Structural transitions and the melting behavior of crystalline, model poly(ethylene oxide), (CH₂-CH₂-O)_n, (PEO) has been investigated using fully atomistic, constant pressure-constant temperature (NPT) molecular dynamics simulations. Melting of PEO proceeds in two stages; order parameters reveal the loss of interchain orientational correlations and of chain helicity in the first and second stages of melting, respectively. Sliding diffusion and anisotropic reorientational dynamics of the polymer backbone are observed in the solid state, in agreement with ¹H NMR experiments.