Structural Color of Colloidal Clusters as a Tool to Investigate Structure and Dynamics

Abstract

Colloidal assemblies have applications as photonic crystals and templates for functional porous materials. While there has been significant progress in controlling colloidal assemblies into defined structures, their 3D order remains difficult to characterize. Simple, low‐cost techniques are sought that characterize colloidal structures and assist optimization of process parameters. Here, structural color is presented to image the structure and dynamics of colloidal clusters prepared by a confined self‐assembly process in emulsion droplets. It is shown that characteristic anisotropic structural color motifs such as circles, stripes, triangles, or bowties arise from the defined interior grain geometry of such colloidal clusters. The optical detection of these motifs reliably distinguishes icosahedral, decahedral, and face‐centered cubic colloidal clusters and thus enables a simple yet precise characterization of their internal structure. In addition, the rotational motion and dynamics of such micrometer‐scale clusters suspended in a liquid can be followed in real time via their anisotropic coloration. Finally, monitoring the evolution of structural color provides real‐time information about the crystallization pathway within the confining emulsion droplet. Together, this work demonstrates that structural color is a simple and versatile tool to characterize the structure and dynamic properties of colloidal clusters.

Supraparticles for Sustainability

“…While photonic SPs can be generated via colloidal assembly in a slowly evaporating droplet, [ 12,194,201 ] microfluidic fabrication is also suitable for the creation of structural colors. [ 202 ] Park et al.…”

Visual Ozone Sensor: Structural Color Change of Pendant Selenium‐Containing Maleimide Polymers via Oxidation

“…Many methods have been developed to construct PCs, such as bulk assembly of block polymers, [23][24][25][26] self-assembly of monodisperse microspheres, [32][33][34][35][36][37] artificial alternating multilayer structures, [38,39] inverse opal templates, [40][41][42][43][44][45] etc. The key process of these methods lies in the construction of periodic arrangements.…”

Programming Self-Assembled Materials With DNA-Coated Colloids

“…Colloids are particles made from almost all compositions (metals, semiconductors, polymers, and oxides), with sizes ranging from several nanometers to several micrometers. The self-assembly of colloidal particles into superstructures holds much potential in applications including plasmonic [27], photonics [28], catalysis [11], and sensing [29]. Conventionally, the word "colloids" specifically refers to particles that are micrometers or submicrometers in size, whereas "nanoparticles" are those generally below 100 nm.…”