Collective filament wrapping and nested spiral formation in active polydisperse systems

Area of Science:

• Soft Matter Physics
• Active Matter Systems
• Non-equilibrium Thermodynamics

Background:

• Monodisperse active systems exhibit single-filament spiraling.
• Polydisperse systems introduce complexity through varied component sizes.
• Understanding self-assembly in active matter is crucial for designing novel materials.

Purpose of the Study:

• Investigate collective behavior in two-dimensional polydisperse suspensions of self-propelled semiflexible filaments.
• Reveal novel self-assembly mechanisms driven by filament length disparity.
• Explore the role of activity levels on emergent structures and dynamics.

Main Methods:

• Computer simulations of a two-dimensional polydisperse suspension.
• Analysis of filament configurations and collective dynamics.
• Utilized van Hove distributions to characterize particle motion.

Main Results:

• Discovered a collective wrapping mechanism absent in monodisperse systems.
• Observed nested spiral structures formed by long filaments coiling around shorter ones.
• Identified structural transitions and dissolution of spirals with increasing activity.
• Revealed coexisting confined and motile filament populations.

Conclusions:

• Filament length disparity is a key control parameter for nonequilibrium self-assembly.
• Inter-filament wrapping is a minimal mechanism for hierarchical organization in active matter.
• This mechanism models cooperative confinement and structural hierarchy in biological and synthetic systems.