Understanding the dynamics of closely packed microgel particles

Soft particles such as microgel suspensions have important applications in industry, which exploit their unusual structural and rhelogical properties. Despite their relevance, the fundamental physics that controls their behavior remains poorly understood. Intriguingly, microgels act as fluid even at high density. Techniques such as rheology, microscopy, and light scattering have been used to probe the macroscopic properties of these materials -- however, the underlying physical mechanisms demand further investigation. We use confocal microscopy to image the local dynamics of highly packed microgels. The gel particles are tracked over time to obtain information about the short and long range correlations of the local particle motion. We probe their response to changes in environmental factors such as temperature or pH using light scattering. The results obtained not only help us understand the origins of the observed macroscopic behavior, but also give us information on the dynamics of glassy arrest in general.