Controlled interfacial assembly of 2D curved colloidal crystals and jammed shells

TL;DR

This paper introduces a microfluidic technique for visualizing and controlling the assembly of colloidal particles into curved 2D crystals and jammed shells, enabling tailored material properties with high precision.

Contribution

It presents a novel microfluidic approach to directly observe and manipulate colloidal crystal growth on curved interfaces, overcoming previous limitations in material control.

Findings

Successful visualization of colloidal crystal growth dynamics

Controlled formation of stable jammed shells ('colloidal armour')

Enhanced control over shell composition, size, and stability

Abstract

Assembly of colloidal particles on fluid interfaces is a promising technique for synthesizing two-dimensional micro-crystalline materials useful in fields as diverse as biomedicine1, materials science2, mineral flotation3 and food processing4. Current approaches rely on bulk emulsification methods, require further chemical and thermal treatments, and are restrictive with respect to the materials employed5-9. The development of methods that exploit the great potential of interfacial assembly for producing tailored materials have been hampered by the lack of understanding of the assembly process. Here we report a microfluidic method that allows direct visualization and understanding of the dynamics of colloidal crystal growth on curved interfaces. The crystals are periodically ejected to form stable jammed shells, which we refer to as colloidal armour. We propose that the energetic barriers to interfacial crystal growth and organization can be overcome by targeted delivery of colloidal particles through hydrodynamic flows. Our method allows an unprecedented degree of control over armour composition, size and stability.