Connectivity-Altering Monte Carlo Simulations of the End Group Effects on Volumetric Properties for Poly(ethylene oxide)

Connectivity-altering Monte Carlo simulations have been used to study structure−property relationships of poly(ethylene glycol) (PEG) and poly(ethylene oxide) dimethyl ether (PEODME) using the recently developed transferable potentials for phase equilibria united atom (TraPPE-UA) ether and alkanol force fields. The combination of end-bridging and double-bridging Monte Carlo simulation techniques is shown to do a good job of equilibrating moderate to high molecular weight polymer melts. Results give excellent agreement between experiment and simulation for liquid densities at a variety of temperatures, pressures, and molecular weights. Comparisons are also made with experiment for structural properties, including the structure factor, chain mean squared end-to-end distance, and radius of gyration, showing good agreement with experiment. Moreover, a thorough microscopic analysis is performed on the different end group effects of PEG and PEODME, determining the excluded volume and liquid structure around the end groups, and linking these to their volumetric properties.