Shape-Selective Self-Assembly and Confinement Dynamics of Colloidal Particles: Exploring Depletion Interactions in Confined Geometries

Abstract

This manuscript examines the interactions among colloidal particles, specifically emphasizing depletion and hydrodynamic interactions in confined geometries. The initial section delves into particle-particle and particle-surface depletion interactions, utilizing a combination of numerical modeling and experimental techniques. Current applications of depletion interactions predominantly involve colloidal destabilization for processes like aggregation and filtration. This work, however, models and experimentally demonstrates shape-selective depletion-induced self-assembly, with the goal of fabricating two-dimensional and three-dimensional structures at the nano- and microscale. Through numerical modeling, we calculated the interaction strengths for basic geometries, which informed our experimental strategies to enhance selectivity. These investigations pinpointed crucial parameters and design principles that optimize shape-selective interactions within complex architectures. The subsequent section presents experimental findings on the confinement dynamics of hard colloids. While the behavior of hard sphere suspensions has been widely researched, understanding their dynamics under confinement is essential. Employing an experimental setup that utilized monodisperse silica spacers to form uniform confinement cells, we measured the hindered diffusivities of hard spheres. Our results indicate that these hard colloids demonstrate consistent behavior across varying levels of confinement. The dynamics of these particles, primarily governed by their rigid structures, highlight important characteristics related to confinement effects, contributing valuable insights into the hydrodynamic interactions of hard spheres.

Keywords

• Self-Assembly and Confinement Dynamics