Thermodynamic Perturbation Theory for Charged Branched Polymers.

Area of Science:

• Polymer Science
• Theoretical Chemistry
• Computational Physics

Background:

• Classical density functional theory (DFT) is used for polymer studies.
• First-order thermodynamic perturbation theory (DFT-TPT1) models nonbonded chain connectivity.
• Second-order TPT (TPT2) is crucial for polymer topology but lacks an effective triple correlation function (CF).

Purpose of the Study:

• To propose an effective triple correlation function (CF) for TPT2.
• To incorporate this into DFT (DFT-eTPT2) for improved polymer brush modeling.
• To enhance the description of excluded-volume effects and electrostatic correlations in branched polymers.

Main Methods:

• Developed an effective triple correlation function (CF).
• Integrated the CF into DFT using second-order thermodynamic perturbation theory (DFT-eTPT2).
• Validated results against molecular dynamics simulations.

Main Results:

• DFT-eTPT2 significantly improves upon DFT-TPT1 for polymer brush density profiles.
• The new method accurately predicts structural features, including peaks near branching points.
• Performance was validated for both neutral and charged branched polymer brushes.

Conclusions:

• DFT-eTPT2 provides a precise and efficient theoretical tool for branched polymer analysis.
• The method offers valuable molecular-level insights into polymer brush structures.
• This advancement aids in understanding complex polymer systems.