Direct Visualization of Colloidal Particle Growth and Assembly Dynamics on Nanometer and Micron Length Scales

Taylor J. Woehl

Assistant Professor of Chemical and Biomolecular Engineering
University of Maryland

Nanoscale growth and assembly phenomena are ubiquitous to many important natural and synthetic systems. If assembly mechanisms are understood fundamentally, synthetic nanomaterials can be assembled into complex materials with applications in catalysis, sensors, and optical materials. In the last decade, liquid cell electron microscopy has emerged as a powerful tool for observing nanoscale dynamics in real-time with nanometer spatial resolution. In this talk, I will present work on real-time visualization of liquid-phase nanoparticle nucleation, growth, and assembly with liquid cell electron microscopy, as well as present results on manipulation and assembly of micron and nano-scale colloidal particles via AC electric fields. The talk will focus on applying kinetic-, transport-, and interaction-based models to interpret the dynamics and mechanisms of micro- and nanoparticle growth and assembly. I will discuss dominant electrokinetic phenomena underling assembly and complex interaction potential energy landscapes observed in colloidal systems and demonstrate how these forces could be used to manipulate plasmonic nanoparticles to enable reconfigurable optical materials. Future research avenues for applying fundamental understanding of nanoscale transport phenomena and assembly to understand electrocatalyst degradation will also be discussed.