Dynamical Arrest Transition in Nanoparticle Dispersions with Short-Range Interactions

We measure the dynamical arrest transition in a model, thermoreversible, adhesive hard sphere dispersion. At low volume fractions phi, below the critical point, gelation occurs within the gas-liquid phase boundary. For phi slightly below and above the critical concentration, the phase boundary follows the predicted percolation transition. At high phi, it melds into the predicted attractive-driven glass transition. Our results demonstrate that for phi above similar to 20% physical gelation is an extension of the attractive-driven glass line and occurs without competition for macroscopic phase separation.