Continuum Modelling for Interacting Coronene Molecules with a Carbon Nanotube.

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Carbon nanotubes (CNTs) facilitate the production of single-dimensional carbon structures.
• Coronene molecules, flat polycyclic aromatic hydrocarbons, can be encapsulated within CNTs.
• The radius of CNTs dictates the achievable configurations of encapsulated coronene, leading to stacked columns or nanoribbons.

Purpose of the Study:

• To analytically model the potential energy of coronene dimers and single coronene molecules inside CNTs.
• To investigate the stacking behavior of coronene molecules within CNTs.
• To determine how molecular stacking affects the preferred orientation (tilt angle) of coronene molecules.

Main Methods:

• Utilizing a continuous model and the Lennard-Jones potential for analytical formulation.
• Modeling coronene molecules as circular rings of carbon atoms with an outer hydrogen ring.
• Modeling carbon nanotubes as circular tubes.
• Analyzing the energy landscape for single coronene and stacked coronene configurations within specific CNTs ((18,0) and (19,0) zigzag CNTs).

Main Results:

• An analytical expression for the potential energy of coronene dimers and encapsulated coronene was derived.
• The minimum energy tilt angle for stacked coronene molecules differs from that of a single coronene molecule within the same nanotube.
• For (18,0) and (19,0) zigzag CNTs, the minimum energy tilt angles observed for single coronenes (approximately 42° and 20°, respectively) were not found in the stacked configurations.

Conclusions:

• The spatial arrangement and interactions of coronene molecules are significantly influenced by their confinement within carbon nanotubes.
• Stacking coronene molecules introduces new energetic considerations that alter their preferred orientation compared to isolated molecules.
• This study provides a foundational understanding for designing and controlling molecular self-assembly within one-dimensional nanostructures.