Metastable Self-Assembled Structures Formed During Dynamic Processes

Self-organization of nanomaterials is not only driven by thermodynamics, but more frequently, is influenced by local metastable local states that inevitably exist during many nonequilibrium processes. The experimental factors that drive the system into these metastable states are many, such as liquid evaporation, anisotropic particle-particle interactions, particle -interface interactions and external applied mechanical forces. Tracking these assembly process thus requires developing <i>in situ</i> characterization techniques. In the talk, I will illustrate several examples of self-assembled metastable structures that involve spherical nanoparticles and nanorods using in situ real space optical microscopy imaging and q-space small angle x-ray scattering technique. I will show the experimental conditions that lead to the formation of two-dimensional crystals and gels during evaporation process and dynamical crystal formation in a shear cell.