The Analysis of the Dynamics of Microgels and Their Assemblies Using Light Scattering Techniques

This chapter reviews recent advances in the understanding of the dynamics of colloidal gel particles (microgels), with a focus on their soft and deformable nature. Using dynamic light scattering, the time–intensity correlation function has been widely used to probe microgel dynamics as a function of volume fraction ( ϕ ). As ϕ increases, a clear transition is observed from ergodic to nonergodic behavior, accompanied by a mode shift from translational to cooperative diffusion, commonly referred to as the “gel mode.” Unlike hard-sphere colloidal glass systems, the gel mode persists even beyond the random close packing fraction, highlighting the unique dynamics of soft colloids. This review also discusses how quantitative analysis of the ϕ-dependent dynamics provides microscopic insight into local deswelling behavior in the glassy state, which is attributed to dehydration of soft microgels. Overall, this chapter aims to provide a comprehensive overview of the dynamic behavior of soft colloidal suspensions and their relevance to gelation, vitrification, and soft matter physics.