In situ investigation of particle clustering dynamics in colloidal assemblies using fluorescence microscopy

• Published in: Journal of colloid and interface science Vol. 576; pp. 195 - 202
• Main Authors: Suh, Youngjoon, Gowda, Hamsa, Won, Yoonjin
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.09.2020
• Subjects: cracking; crystals; fluorescence; fluorescence microscopy; Grain boundary; In situ measurements; Laser induced fluorescence; mechanics; Saturation level; Self-assembly; In situ measurements; Self-assembly; Saturation level; Laser induced fluorescence; Grain boundary
• ISSN: 0021-9797; 1095-7103; 1095-7103
• DOI: 10.1016/j.jcis.2020.04.054

Herein, particle clustering dynamics and thermofluidic transprot in colloidal assemblies are experimentally examined using a novel fluorescence technique with the aim to investigate colloidal physics that decide cracking mechanics during self-assembly. The results show that grain boundaries are determined by dynamic structuring regimes governed by the film’s saturation level. [Display omitted] Colloidal self-assembly is a process in which dispersed matter spontaneously form higher-order structures without external intervention. During self-assembly, packed particles are subject to solvent-evaporation induced dynamic structuring phases, which leads to microscale defects called the grain boundaries. While it is imperative to precisely control detailed grain boundaries to fabricate well-defined self-assembled crystals, the understanding of the colloidal physics that govern grain boundaries remains a challenge due to limited resolutions of current visualization approaches. In this work, we experimentally report in situ particle clustering dynamics during evaporative colloidal assembly by studying a novel microscale laser induced fluorescence technique. The fluorescence microscopy measures the saturation levels with high fidelity to identify distinct colloidal structuring regimes during self-assembly as well as cracking mechanics. The techniques discussed in this work not only enables unprecedented levels of colloidal self-assembly analysis but also have potential to be used for various sensing applications with microscopic resolutions.