Anisotropic colloidal particles near boundaries

Abstract

Anisotropic colloidal particles are regularly found in applications ranging from health to energy. These particles, typically with non-uniform shape or surface chemistry, interact with boundaries in unique ways, offering pathways to complex assemblies and active systems. Work in this field over the past two decades rapidly advanced, with the last five years seeing significant innovation. One common thread joining many studies and applications is that of the presence of boundaries in the form of a nearby wall or neighboring particle. Asymmetry introduced by a neighboring boundary often leads to unique and surprising particle dynamics from the resulting anisotropic surface interactions. Herein, we provide background for the area, some recent distinctive examples, and describe recent work from our group developing a technique to measure surface interactions of anisotropic particles. Note that we focused on anisotropic “colloidal” particles with the size ranging from 0.1 to 10  μm in the presence of externally or internally generated fields. Within this context, we then motivate and describe recent work from our group developing an ultra-microscopy technique called Scattering Morphology Resolved Total Internal Reflection Microscopy. Finally, we finish the perspective article by identifying challenges and providing an outlook for the field.