Crystal Comets: A Geometric Model for Sculpting Anisotropic Particles from Emulsions

Area of Science:

• Materials Science
• Colloid and Interface Science

Background:

• Microscopic high aspect ratio particles are crucial for applications like active ingredient delivery and food stabilization.
• Existing methods for producing these particles often lack scalability or precise control over particle morphology.

Purpose of the Study:

• To develop a simple, scalable, and controllable method for producing microscopic high aspect ratio particles.
• To investigate the relationship between process parameters and particle morphology.

Main Methods:

• Utilized an oil-in-water emulsion system where droplets were quenched and crystallized.
• Employed surfactants to facilitate the ejection of the solid oil phase from the liquid precursor.
• Tuned surfactant concentration and quench depth to control ejection and crystallization rates, promoting anisotropic growth.

Main Results:

• Achieved a scalable process for producing particles with continuously controllable aspect ratios.
• Demonstrated that anisotropic particle growth occurs through continuous ejection of solidified oil.
• An analytical geometric model predicted accessible morphologies, correlating crystal aspect ratio with surfactant concentration via growth angle variations.

Conclusions:

• The developed method offers precise control over particle aspect ratio through surfactant concentration and quench depth.
• The findings provide a deeper understanding of anisotropic particle formation mechanisms.
• This technique holds potential for advancing applications requiring tailored microparticle properties.