Topology controls flow patterns in active double emulsions.

Area of Science:

• Physics
• Materials Science
• Soft Matter Physics

Background:

• Active emulsions and liquid crystalline shells represent experimentally accessible topological matter.
• Understanding nonequilibrium states in active matter is crucial for developing novel materials and devices.

Purpose of the Study:

• To numerically investigate the morphology and dynamics of double emulsions with embedded passive droplets.
• To explore the emergence of novel nonequilibrium states driven by particle activity.

Main Methods:

• Numerical simulations of double emulsions containing one or two passive droplets within a larger active droplet.
• Analysis of system morphology, spatiotemporal dynamics, and topological defect formation.

Main Results:

• A single active droplet within a double emulsion exhibits self-motility, transitioning between translational and rotational motion without defects.
• A pair of particles can nucleate disclination loops, leading to rotor or chaotic oscillator dynamics by tuning activity.
• Topological defects, specifically disclination loops, can power rotation and exhibit complex 3D dynamics, forming active living polymers.

Conclusions:

• Active emulsions offer a controlled pathway to generate flow and topological patterns in active matter.
• These systems provide an alternative to bulk active matter, which often results in less controllable active turbulence.
• The study highlights the potential for self-assembly and controlled manipulation of topological states in active emulsions.