Structure and dynamics of supercooled suspensions composed of fractal colloids

The glass transition is an out of equilibrium transition from the fluid to a disordered solid obtained at very high volume fractions. The glass transition is a dynamical arrested transition where colloids are trapped within the cage formed by their neighbors. The absence of rearrangement on long time scales leads to the solid behavior of the suspension. This transition has been well studied for hard-sphere colloids. Here, we aim to study this transition for fractal colloids, namely fumed silica dispersed in a good solvent. Preliminary results show that this system presents two originalities compared to hard-sphere colloidal systems. As the volume fraction is increased, the system viscosity diverges at low volume fraction, 30% and the colloids interpenetrate each other. Using SAXS and XPCS, we will systematically explore the structure and dynamics of fumed silica dispersion as a function of their volume fraction. We aim to unravel the role of interpenetration in glass forming liquids.