Solvation effects for polymers at an interface: a hybrid self-consistent field-density functional theory approach

Area of Science:

• Polymer Physics
• Statistical Mechanics
• Computational Chemistry

Background:

• Understanding polymer solvation is crucial for predicting polymer behavior in solution and at interfaces.
• Existing theories often simplify or neglect complex solvation interactions.

Purpose of the Study:

• To systematically incorporate solvation effects into Wertheim's thermodynamic perturbation theory (TPT).
• To develop and validate approximate solvation potentials for polymer systems.
• To investigate the impact of solvation on polymer conformations near a hard wall.

Main Methods:

• Application of polyatomic density functional theory (DFT) by Kierlik and Rosinberg.
• Derivation of two approximate solvation potentials based on reference unbonded fluid correlation functions.
• Validation against many-chain Monte Carlo (MC) simulations.
• Self-consistent field theory (SCFT) calculations for polymers at a hard wall.

Main Results:

• TPT approximations provide a systematic, albeit simplified, inclusion of solvation effects.
• The TPT(M-1) approximation shows reasonable agreement with MC simulations for bulk end-to-end distances.
• The TPT2_e approximation yields less accurate, shorter-ranged solvation potentials.
• Inclusion of solvation significantly improves SCFT predictions of polymer end-to-end vector components near a hard wall, with minor impact on density profiles.

Conclusions:

• The developed TPT approximations offer a computationally tractable method for modeling polymer solvation.
• These improved models enhance the accuracy of predicting polymer conformations and properties, particularly in confined geometries.
• The study highlights the importance of solvation in polymer physics, especially for interfacial phenomena.