Molecular dynamics simulations of 1,2-dimethoxyethane in aqueous solution: Influence of the water potential

We have performed molecular dynamics simulations of aqueous solutions of 1,2-dimethoxyethane (DME), an oligomer of poly(ethylene oxide), employing several potentials for water. Specifically, we investigated the structural, conformational, and dynamic properties of DME/water solutions as a function of composition using the TIP4P, MCY, SPC, and SPC/E potentials for water. DME/DME interactions were described using our previously derived quantum-chemistry-based potential, while the DME/water potential was parametrized for each water model to best represent the energy of a DME/water complex as determined from high-level quantum chemistry calculations. For dilute (water-rich) solutions, static and dynamic properties were found to depend only weakly on the water model employed. For more concentrated solutions, important differences between the models were observed, particularly in the structure of the solutions (e.g., the size of water clusters) and the self-diffusion coefficient of water.