Engineering Morphologies of Metal-Based Colloidal Assemblies via Colloid Jamming at Liquid-Liquid Interfaces

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Colloidal assemblies are crucial for applications like photonic devices and energy storage.
• Diverse observed morphologies lack a clear understanding of formation mechanisms.
• Evaporation-induced self-assembly in microfluidics is a key fabrication technique.

Purpose of the Study:

• To investigate the influence of coordination interactions between metal sulfide nanoparticles (MS NPs) and fluorosurfactants on assembly morphology.
• To understand how nanoparticle concentration and interfacial properties affect self-assembly outcomes.
• To provide a framework for engineering colloidal assembly structures.

Main Methods:

• Evaporation-induced self-assembly within droplet microfluidics.
• Systematic variation of metal sulfide nanoparticle (MS NP) concentration and coordination strength.
• Utilizing core-shell nanoparticles (MS@SiO2 NPs) to eliminate interfacial interactions.
• Characterization of assembly morphologies.

Main Results:

• Coordination interactions at the droplet interface significantly dictate assembly morphology.
• Coating MS NPs with SiO2 shells effectively mitigates interfacial interactions.
• Assembly morphology can be precisely engineered by adjusting MS NP concentration under coordination control.
• Construction of core-shell and homogeneously distributed binary colloidal assemblies via interfacial jamming.

Conclusions:

• Coordination interactions and concentration are critical factors in shaping colloidal assemblies during evaporation-driven self-assembly.
• This work establishes a foundation for designing functional materials with controlled architectures.
• The findings are applicable to developing materials for catalysis, plasmonics, and porous applications.