Gel and glass transition in fragile colloidal clays

Dynamic Light Scattering (DLS) measurements were performed on colloidal suspensions of Laponite® at different concentrations in the range C = (1:5÷3:0)%. The slowing down of the dynamics induced by aging was monitored by following the temporal evolution of autocorrelation functions at different concentrations towards the gel and glass transition. Exploiting analogies with supercooled liquids approaching their glass transitions, an Angell plot for the structural relaxation times was drawn. Finally, the fragility of Laponite® suspensions at different concentrations, in different solvents, at two salt concentrations and with the addition of a polymer was reported and discussed.