Modeling of amorphous polyaniline emeraldine base.

Area of Science:

• Materials Science
• Computational Chemistry
• Polymer Science

Background:

• Polyaniline emeraldine base is a conductive polymer with potential applications.
• Understanding its amorphous structure is crucial for material property prediction.
• Atomistic simulations offer a powerful tool for investigating polymer behavior.

Purpose of the Study:

• To investigate the amorphous structure of polyaniline emeraldine base using molecular dynamics.
• To develop and validate a reliable force field for simulating polyaniline.
• To elucidate the preferred interactions between polymer repeating units.

Main Methods:

• Atomistic classical molecular dynamics simulations (750 ns trajectory).
• Testing and validation of various force-field parameters (atomic charges, van der Waals parameters).
• Quantum mechanical (QM) and QM/molecular mechanics (QM/MM) calculations for validation.

Main Results:

• A validated force field successfully reproduced experimental polyaniline density.
• Simulations identified favored interactions between amine and imine nitrogen-containing repeating units.
• Partial radial distribution functions confirmed short-range intramolecular correlations, aligning with experimental findings.

Conclusions:

• The developed force field accurately models amorphous polyaniline emeraldine base.
• Specific inter-unit interactions significantly influence the polymer's structure.
• Simulation results provide valuable insights into polyaniline's amorphous state and short-range order.