Fluorescence correlation spectroscopy in polymer science
Fluorescence correlation spectroscopy (FCS) is a well-established technique for studying dynamic processes and interactions with minimal invasion into the corresponding system. Even though FCS has been mainly applied to biological systems, within the last 15 years an increasing number of studies in material sciences have appeared, demonstrating its enormous potential also for this field. Apart from investigations on colloidal systems, polymer science has benefited significantly from this technique. This review will summarize FCS studies on polymer systems and, in particular, focus on the diffusion of differently sized molecular and macromolecular probes in polymer solutions, classical and responsive polymer gels, polymer melts and glasses. It will be discussed how FCS can be used to determine translational and rotational diffusion in polymer solutions and at interfaces, scaling laws, micellization and aggregation and, to some extent, polymer structure including heterogeneity. Thus, FCS should be considered a powerful complement to other methods for the investigation of polymer structure and dynamics.