Defect topologies in a nematic liquid crystal near a patchy colloid

Area of Science:

• Soft Matter Physics
• Materials Science
• Computational Physics

Background:

• Colloidal particles in liquid crystals create complex defect structures.
• Defect formation is driven by surface anchoring and far-field director alignment.
• Understanding these defects is crucial for liquid crystal display technology and advanced materials.

Purpose of the Study:

• To investigate defect topologies around spherical colloidal particles in nematic liquid crystals using simulations.
• To explore the impact of homogeneous and heterogeneous surface anchoring on defect formation.
• To identify and characterize novel defect structures not previously reported.

Main Methods:

• Isothermal-isobaric Monte Carlo simulations were employed.
• Spherical colloidal particles with varying surface anchoring properties were modeled.
• Defect structures were analyzed based on the competition between surface and far-field director orientations.

Main Results:

• Well-known surface and saturn ring defects were observed for homogeneous perpendicular anchoring.
• A boojum defect topology was identified for homogeneous parallel anchoring, matching experimental but not prior simulation results.
• Novel boojum ring and two other previously unreported defect topologies were observed for heterogeneous patchy colloids.

Conclusions:

• The study successfully simulated various defect topologies in nematic liquid crystals with colloidal particles.
• It provides new insights into defect formation mechanisms, particularly for heterogeneous colloids.
• The findings offer a basis for further experimental and theoretical investigations into complex liquid crystal systems.