Nematic liquid crystals of bifunctional patchy spheres

Area of Science:

• Soft Matter Physics
• Materials Science
• Theoretical Chemistry

Background:

• Anisotropic interactions drive self-assembly into semi-flexible chains, forming nematic liquid crystal phases.
• Previous studies utilized minimalist models of hard cylinders with attractive sites, validated by numerical simulations.
• A simplified theoretical approach has shown promise in capturing the properties of self-assembly-driven liquid crystals.

Purpose of the Study:

• To investigate a simpler model of bifunctional Kern-Frenkel hard spheres for self-assembly into semi-flexible chains.
• To compare numerical estimates of isotropic-nematic phase boundaries with theoretical predictions for this simplified model.
• To assess the validity of the Onsager trial function in modeling particle orientation during aggregation.

Main Methods:

• Numerical simulations were employed to estimate isotropic-nematic phase boundaries.
• A simplified theoretical treatment, adapted from cylinder-like particles, was applied.
• The accuracy of the Onsager trial function for particle orientation in aggregated systems was evaluated.

Main Results:

• The simplified theoretical predictions showed good agreement with accurate numerical estimates of phase boundaries.
• The model of bifunctional Kern-Frenkel hard spheres successfully undergoes an isotropic-nematic transition via self-assembly.
• The study provides an assessment of the Onsager trial function's applicability in aggregated systems.

Conclusions:

• A simplified theoretical approach effectively captures the isotropic-nematic phase behavior of self-assembling spheres.
• The Kern-Frenkel hard sphere model offers a simpler alternative for studying self-assembly-driven liquid crystals.
• Further validation of the Onsager trial function in aggregation scenarios is supported by these findings.