A molecular dynamics model of the amorphous regions of polyethylene oxide

We report a molecular dynamics model of the amorphous regions of polyethylene oxide for use in study of the ionic transport mechanisms in this polymer when it is used as an electrolyte in batteries. The model is produced by beginning with a molecular dynamics of dimethyl ether which we have reported earlier and "polymerizing" it computationally by successively choosing pairs of unbonded methyl groups and changing the forces to describe the chemical bond in the polymer. This is not intended to be a fully realistic simulation of the actual chemical polymerization process, but we argue that it produces a useful model of a sample of the amorphous polymer. We report structural and dynamical properties of the resulting model, in which we have adopted torsion forces reported by Krimm and coworkers to fit the observed vibrational spectrum.