A COMPUTER-SIMULATION STUDY OF THE CHAIN CONFIGURATIONS IN POLY(ETHYLENE OXIDE)-HOMOLOG MELTS

The configurations of a series of diethyl ether chain molecules with the general formula C2H5-O-(CH2-CH 2-O)m-C2H5, i.e., homologs of poly(ethylene oxide), PEO, have been determined from NpT molecular dynamics simulations of the pure melts at 400 K. The fraction of trans conformers, the mean square radii of gyration, and the mean square end-to-end distances have been compared to those predicted by a pivot Monte Carlo sampling method based on the assumption that chain configurations in the melt are largely determined by highly localized intramolecular near-neighbor interactions. Discrepancies are significant and point to inadequacies in the latter picture when Coulomb potentials are explicitly taken into account. © 1995 American Institute of Physics.