A Classical Density Functional Theory for Predicting Energy and Orientation Properties of Chain-Like Molecules on...

Area of Science:

• Materials Science
• Physical Chemistry
• Computational Physics

Background:

• Understanding chain-like molecule orientation is crucial across various scientific fields.
• Theoretical frameworks for predicting molecular orientation on surfaces are limited.
• Interfacial behavior significantly impacts material properties and applications.

Purpose of the Study:

• To develop and apply a classical density functional theory (CDFT) for investigating chain-like molecule orientation.
• To analyze the energy properties and orientational behavior of molecules on structured interfaces.
• To explore the influence of interfacial structure on molecular arrangement and interactions.

Main Methods:

• Implementation of a 3D classical density functional theory (CDFT) algorithm.
• Modeling interfaces using faces of a body-centered cubic (BCC) crystal.
• Comparison of theoretical predictions with results from molecular simulations.

Main Results:

• CDFT predictions for potential mean force (PMF), density profiles, and orientation order parameters align with molecular simulations.
• A bimodal orientation distribution and a vertical-horizontal transition were observed, dependent on surface separation.
• Different BCC crystal faces ((111), (100), (110)) exhibit distinct effects on interfacial properties.

Conclusions:

• The study provides a robust theoretical framework for understanding molecular orientation at interfaces.
• Interfacial structure critically dictates molecular behavior, including PMF, density, and orientation.
• Findings offer valuable insights for designing advanced nanoparticles and porous adsorbents.