Deposition control of model glasses with surface-mediated orientational order

Area of Science:

• Materials Science
• Chemical Physics
• Statistical Mechanics

Background:

• Anisotropic molecules can form solids with complex structures.
• Understanding orientational order in materials is crucial for their properties.
• Nonequilibrium processes often lead to unique material structures.

Purpose of the Study:

• To introduce a minimal model for solid-forming anisotropic molecules.
• To investigate surface and bulk orientational order in thermal equilibrium and nonequilibrium conditions.
• To develop methods for fabricating materials with uniform orientational order.

Main Methods:

• Developed a minimal theoretical model for anisotropic molecules.
• Simulated thermal equilibrium and nonequilibrium growth processes.
• Employed evolutionary algorithms to design oscillatory growth protocols.

Main Results:

• The model exhibits surface orientational order without bulk order in equilibrium.
• The model accurately reproduces experimental observations of nonequilibrium growth with deposited surface order.
• A growth-poisoning mechanism was identified, leading to nonuniform order.
• Oscillatory protocols were designed to achieve uniform order in nonequilibrium structures.

Conclusions:

• Minimal models can capture complex phenomena in anisotropic molecular self-assembly.
• Nonequilibrium growth can inherit equilibrium surface order, but often nonuniformly.
• Protocol design offers a pathway for controlled fabrication of ordered materials.