XPCS: Nanoscale motion and rheology

X-ray photon correlation spectroscopy (XPCS) has emerged as a powerful technique for investigating slow, nanometer-scale structural dynamics in materials. This paper reviews major directions of recent XPCS research on complex fluids where significant information relevant to their rheological behavior has been obtained. The review focuses on three topics: block-copolymer phases, colloidal glasses and gels, and polymer thin-film surfaces and interfaces. The paper also discusses important anticipated developments for XPCS in the near future and describes some particularly promising directions for the technique in advancing understanding of complex-fluid rheology, including the application of XPCS to microrheology.