Kinetically arrested periodic clusters in active filament arrays

Area of Science:

• Soft Matter Physics
• Active Matter Systems
• Polymer Dynamics

Background:

• Ordered arrays of active semi-flexible filaments are common in biological systems.
• Understanding their self-assembly into ordered structures is crucial for various applications.
• Previous studies have explored filament dynamics but lacked detailed analysis of cluster formation in ordered arrays.

Purpose of the Study:

• To investigate the dynamics and pattern formation of ordered arrays of active semi-flexible filaments.
• To elucidate the physical mechanisms governing the self-assembly of these filaments into compact clusters.
• To establish relationships between system parameters and emergent cluster characteristics.

Main Methods:

• Utilized two-dimensional Brownian dynamics simulations.
• Modeled filaments as connected chains of polar active particles with follower forces.
• Analyzed the influence of activity, array geometry, filament elasticity, and grafting density.

Main Results:

• Demonstrated self-assembly into regularly spaced, kinetically arrested compact clusters for specific parameter ranges.
• Identified crucial roles of activity, array geometry, filament elasticity, and grafting density in influencing cluster size, shape, and spacing.
• Observed self-similar cluster shapes with activity-dependent scaling exponents for varying grafting densities.

Conclusions:

• Derived theoretical expressions linking cluster number and spacing to filament activity, elasticity, and grafting density.
• Provided insights into the initiation of clustering through the balance of steric, friction, active, and elastic forces.
• Highlighted the importance of these forces in shaping and stabilizing emergent clusters.