A revised quantum chemistry-based potential for poly(ethylene oxide) and its oligomers in aqueous solution

Area of Science:

• Computational chemistry
• Physical chemistry
• Materials science

Background:

• Previous force fields inaccurately described water interactions with poly(ethylene oxide) (PEO) and 1,2-dimethoxyethane (DME).
• Hydrophobic hydration of DME was poorly represented, impacting simulation accuracy.

Purpose of the Study:

• To revise a quantum chemistry-based force field for improved simulation of DME-water interactions.
• To accurately model both hydrophilic and hydrophobic hydration of DME in aqueous solutions.

Main Methods:

• High-level quantum chemistry calculations.
• Development and revision of a quantum chemistry-based force field.
• Molecular dynamics simulations of aqueous DME solutions.

Main Results:

• The revised force field accurately reproduced experimental excess free energy, enthalpy, and volume for DME solutions.
• Simulations showed good agreement with experimental excess solution viscosity and water self-diffusion.
• Revised hydrophobic ether-water interactions significantly reduced excess free energy and enthalpy.

Conclusions:

• The revised force field provides a more accurate representation of DME-water interactions, particularly hydrophobic hydration.
• This improved model enhances the predictive power for aqueous solutions containing DME and PEO oligomers.
• Key solution properties remain largely consistent, indicating robustness of the revised potential.