The glass transition in colloidal suspensions of silica nanoparticles in a water-lutidine mixture: A photon correlation study

We discuss the structural and dynamical properties of a colloidal glass of silica nanoparticles in a water-lutidine mixture probed using photon correlation techniques. We describe the small angle set-up used to perform X-ray photon correlation spectroscopy (XPCS) experiments and the procedure followed to measure the volume fraction of the sample. We describe the structure of the glass using a short range potential model and a theoretical structure factor within the mean spherical approximation. The dynamics finally is characterized by a Gaussian-like intermediate scattering function which is not compatible with the classical picture of an heterogeneous diffusive process.