Asymmetric fluctuations and self-folding of active interfaces

Area of Science:

• Soft matter physics
• Fluid dynamics
• Active matter systems

Background:

• Active fluids, driven by internal energy sources, exhibit complex dynamics.
• Interfaces between different fluid phases are crucial in many natural and engineered systems.
• Microtubule-based active fluids generate unique flow patterns and fluctuations.

Purpose of the Study:

• To investigate the structure and dynamics of interfaces between passive and active fluids.
• To understand the mechanisms behind interfacial fluctuations and asymmetry.
• To explore the role of active stresses in controlling interface morphology and stability.

Main Methods:

• Experimental observations of interfacial behavior.
• Numerical simulations of active fluid dynamics.
• Theoretical analysis of interfacial instabilities and fluctuations.

Main Results:

• Turbulent-like active flows induce significant interfacial fluctuations.
• Asymmetry in interfacial fluctuations is linked to curvature and local vortical flows.
• High activity leads to interface self-folding, passive droplet invagination, and foam formation.

Conclusions:

• Active stresses fundamentally control the structure, dynamics, and breakup of soft interfaces.
• The interplay between active flows and interfacial properties leads to complex emergent phenomena.
• This study provides insights into reconfigurable interfaces relevant to active matter research.