Porous supraparticle assembly through self-lubricating evaporating colloidal ouzo drops

Area of Science:

• Materials Science
• Colloid Science
• Nanotechnology

Background:

• Supraparticle fabrication via evaporating colloidal drops is promising but hindered by contact line pinning, leading to uncontrolled shapes.
• Achieving precise control over supraparticle morphology is crucial for tailoring their properties and applications.

Purpose of the Study:

• To overcome the challenge of contact line pinning in colloidal drop evaporation.
• To develop a self-lubrication strategy for controlled supraparticle assembly.
• To produce supraparticles with tunable shapes and high porosity.

Main Methods:

• Utilizing ternary drops containing colloidal particles, water, ethanol, and anise-oil.
• Inducing the 'ouzo effect' via ethanol evaporation to form coalescing oil microdroplets.
• Establishing a self-lubricating oil ring at the contact line to levitate the drop.
• Allowing water evaporation to form porous supraparticles with fractal-like internal structures.

Main Results:

• Successfully overcame contact line pinning through a self-lubrication mechanism.
• Generated porous supraparticles with tunable shapes and fractal-like internal structures.
• Demonstrated the production of a large number of supraparticles on hydrophobic surfaces.

Conclusions:

• Self-lubrication via the 'ouzo effect' provides an effective strategy for controlled supraparticle fabrication.
• The developed method allows for the production of high-porosity supraparticles with adaptable morphologies.
• This technique offers a versatile route for creating advanced materials for various applications.