Crystallization of Active Emulsion

Area of Science:

• Physics
• Materials Science
• Chemistry

Background:

• Active matter systems exhibit self-organization and phase transitions, offering potential for nonequilibrium materials.
• Fabricating stable crystals in active matter remains a significant challenge.
• Previous research focused on low-density active matter, limiting crystal formation.

Purpose of the Study:

• To introduce a novel method for obtaining stable two-dimensional (2D) crystals in active emulsions.
• To investigate the crystallization process driven by Marangoni flow in active droplets.
• To explore the kinetics and growth mechanisms of these active crystals.

Main Methods:

• Utilized heterogeneous crystallization in an active octane-in-water emulsion.
• Drove active motion via Marangoni flow at droplet interfaces.
• Analyzed crystal growth rate and its dependence on droplet velocity.
• Investigated crystallization kinetics through droplet attachment and detachment processes.

Main Results:

• Achieved formation of stable 2D crystals in active emulsions.
• Observed linear increase in crystal volume over time.
• Identified a maximum in crystal growth rate correlated with average droplet velocity.
• Demonstrated crystallization proceeds through a liquid intermediate phase with decreasing orientational order.

Conclusions:

• The developed method enables the creation of stable 2D crystals in active emulsions.
• Crystal growth kinetics are governed by droplet dynamics and phase transitions.
• This work provides a foundation for developing novel nonequilibrium materials and technologies based on active droplet systems.