Analysis of Atomistic Potentials for Poly(ethylene glycol) Ethers.

Area of Science:

• Computational chemistry
• Polymer science
• Physical chemistry

Background:

• Poly(oxyethylene) (PEO) is a versatile polymer with applications in various fields.
• Accurate molecular modeling is crucial for predicting polymer properties.
• Existing force fields require validation for PEO systems.

Purpose of the Study:

• To evaluate and compare two molecular models, modified TraPPE-UA and modified general AMBER force-field (GAFF), for simulating PEO.
• To assess the accuracy of these models in predicting temperature-dependent properties of PEO in neat and aqueous solutions.
• To adapt a set of charges for the modified GAFF model for PEO of arbitrary size.

Main Methods:

• Utilized the modified TraPPE-UA and modified GAFF models for molecular simulations.
• Simulated neat and aqueous solutions of small PEO oligomers and larger PEO polymers.
• Calculated various temperature-dependent properties for model validation.
• Adapted charges for the modified GAFF model to accommodate PEO chains of varying lengths.

Main Results:

• Both modified TraPPE-UA and modified GAFF models demonstrated good agreement with experimental properties.
• The modified TraPPE-UA model exhibited higher accuracy in reproducing the experimental temperature-dependent properties of PEO.
• The adapted GAFF model provided a viable option for simulating PEO systems.

Conclusions:

• The modified TraPPE-UA model is recommended for accurate simulations of PEO systems.
• Molecular modeling provides a powerful tool for understanding polymer behavior.
• Further refinement of force fields can enhance predictive capabilities for polymer solutions.