Surface ordering of diskotic liquid crystals.

Area of Science:

• Soft Matter Physics
• Computational Chemistry
• Materials Science

Background:

• Diskotic molecules exhibit complex phase behavior, including liquid crystalline phases.
• Understanding molecular interactions at interfaces is crucial for designing advanced materials.
• The Gay-Berne potential is a widely used model for simulating anisotropic molecules.

Purpose of the Study:

• To investigate the influence of disk-wall interactions on the phase transitions of diskotic molecules.
• To model homeotropic (face-on) and planar (edge-on) anchoring using tunable disk-wall potentials.
• To compare simulation results in slab geometry with bulk behavior.

Main Methods:

• Monte Carlo simulations were employed to study diskotic molecules.
• The Gay-Berne potential was used to describe inter-molecular interactions.
• Two distinct disk-wall interaction functions were implemented to model different anchoring scenarios.

Main Results:

• The isotropic-nematic transition temperature remained unchanged compared to bulk simulations.
• The nematic-columnar transition temperature increased for homeotropic anchoring.
• The nematic-columnar transition temperature decreased for planar anchoring.

Conclusions:

• Disk-wall interactions significantly influence the nematic-columnar transition temperature in slab geometry.
• Homeotropic anchoring enhances, while planar anchoring suppresses, the nematic-columnar transition.
• Planar anchoring-induced frustration, arising from competing wall orientations, explains the decreased transition temperature.