Molecular dynamics simulation study of spherical nanoparticles in a nematogenic matrix: anchoring, interactions, and...

Area of Science:

• Materials Science
• Soft Matter Physics
• Computational Chemistry

Background:

• Understanding nanoparticle behavior in liquid crystal matrices is crucial for advanced material design.
• Soft spherocylinders (SSCs) form a nematogenic matrix with unique properties.
• Spherical nanoparticles (NPs) interactions within such matrices are complex and not fully understood.

Purpose of the Study:

• To investigate the phase behavior and aggregation of spherical nanoparticles (NPs) within a soft spherocylinder (SSC) matrix.
• To explore the influence of pressure and NP-SSC interactions on the NP dispersion and matrix structure.
• To elucidate the underlying mechanisms governing NP-NP interactions in this system.

Main Methods:

• Utilizing molecular dynamics (MD) simulations to model the behavior of NPs and SSCs.
• Simulating systems with varying NP concentrations, pressures, and NP-SSC interaction potentials.
• Analyzing particle distribution, phase separation, and interaction forces within the simulated matrix.

Main Results:

• At higher pressures, the NP-SSC mixture demixed into NP-poor nematic and NP-rich isotropic phases.
• At low NP concentrations, a single-phase nematic with dispersed NPs was observed.
• Promoting homeotropic anchoring led to unexpected NP aggregation due to dominant many-body effects, suppressing repulsion.

Conclusions:

• Nanoparticle behavior in soft matter matrices is highly sensitive to interaction potentials and many-body effects.
• Contrary to expectations of enhanced dispersion, homeotropic anchoring promoted NP aggregation.
• The findings highlight the complexity of predicting NP self-assembly in anisotropic fluids.