Scaling up self-assembly: bottom-up approaches to macroscopic particle organization

Area of Science:

• Materials Science
• Soft Matter Physics
• Chemical Engineering

Background:

• Brownian motion drives nanoparticle self-assembly, but larger non-Brownian particles (d > 6 μm) face kinetic limitations.
• Immobilization and kinetic arrest increase with particle radius, hindering autonomous crystalline array formation.

Purpose of the Study:

• To review recent advancements in non-Brownian particle self-assembly.
• To highlight methods for overcoming kinetic arrest in larger particles.
• To discuss the potential of bottom-up macroscale particle assembly for material design.

Main Methods:

• External drivers (e.g., agitation) are employed as artificial "thermalizing forces" to induce motion in non-Brownian particles.
• Exploration of various agitation methods to overcome self-assembly barriers.

Main Results:

• Successful application of external drivers facilitates crystallization in non-Brownian particle systems.
• Bottom-up assembly allows precise control over pore structure and surface properties.
• Achieved control over mechanical strength, diffusive properties, and photonic characteristics.

Conclusions:

• Non-Brownian particle assembly offers a route to engineer materials with properties mimicking natural structures like opals and bone.
• Potential applications include drug delivery, tissue engineering, acoustics, batteries, and filtration.
• This technology enables the creation of advanced materials with tunable hierarchical structures.