In situ Rheology with Small Angle x-ray Scattering and x-ray Photon Correlation Spectroscopy

X-M Lin, J. Lee, Z. Jiang, J. Wang, A.R. Sandy, S. Narayanan
Argonne National Laboratory,
United States

Keywords: rheology, SAXS, XPCS, X-ray

Summary:

Combining rheological measurements with in situ small angle x-ray scattering and x-ray photon correlation spectroscopy (Rheo-SAXS-XPCS) can reveal new insights about the structural reorganization and the dynamics of many colloidal systems under non-equilibrium conditions. Here we will discuss this new capability that is being developed at sector 8-ID of the Advanced Photon Source at Argonne National Lab. Using a highly monodisperse colloidal suspension as a model system, we show that oscillatory shear can induce unique two-step shear thinning/thickening transitions that are associated with different underlying mechanisms. The occurrence of this order-to-disorder transition is affected by yield stress, particle polydispersity, and oscillation frequency. The potential applications of this technology to coating industry will also be discussed.