Publication date: 15th May 2025
In this talk, I will discuss our recent efforts on utilizing liquid-phase TEM imaging and associated machine-learning or computational simulation methods to map the fundamental forces involved in the equilibrium and out-of-equilibrium assemblies of nanoparticles. In equilibrium assembly, we study the nonclassical nucleation pathways, the growth habits, and the phononic relaxation of the nanoparticle self-assemblies. We show that colloidal interactions at the nanoscale can be mapped from the statistical sampling of single particle trajectories, or as effective springs by fitting phonon dispersion spectra. Going beyond equilibrium dynamics, we also study the external field driven assembly of nanoparticles, where electroosmosis effects drive the nanoparticles into active “swarms” with rapidly-changing patterns. We will show new structural control and new functional relevance in these particulate systems, when we consider both the colloidal interactions and all the other factors such as diffusivity, many-body effects, and ionic flows.