A new numerical approach to dense polymer brushes and surface instabilities

Area of Science:

• Polymer Physics
• Computational Materials Science
• Surface Chemistry

Background:

• Densely grafted polymer brushes are crucial in various applications.
• Understanding their behavior under different conditions is essential.
• Existing models often lack detailed information on chain configurations.

Purpose of the Study:

• To present a novel numerical self-consistent field (SCF) method for simulating polymer brushes.
• To compare the performance of the Flory-Huggins model and the Carnahan-Starling equation of state.
• To provide detailed insights into polymer brush chain configurations, including fluctuations and packing.

Main Methods:

• Numerical self-consistent field (SCF) method using freely jointed chains of spherical monomers.
• Comparison with Flory-Huggins model and Carnahan-Starling equation of state.
• Validation against molecular dynamics (MD) simulations and analytical SCF calculations.

Main Results:

• The Carnahan-Starling equation of state is preferable at polymer volume fractions above 10%.
• The numerical SCF method shows close agreement with MD simulations and analytical SCF calculations for density profiles.
• The method provides detailed information on chain configurations, fluctuations, depletion, and packing effects.

Conclusions:

• The developed numerical SCF method accurately describes densely grafted polymer brushes.
• The model successfully reproduces the instability of polymer brushes driven by fluctuation effects.
• This approach offers a powerful tool for studying complex polymer brush phenomena.