We report a novel experimental study on the jamming transition of dry fine powders with controlled attractive energy and particle size. Like in attractive colloids dry fine particles experience diffusion-limited clustering in the fluidlike regime. At the jamming threshold fractal clusters crowd in a metastable state at volume fractions depending on attractive energy and close to the volume fraction of hard nonattractive spheres at jamming. Near the phase transition the stress-(volume fraction) relationship can be fitted to a critical-like functional form for a small range of applied stresses $\sigma \sim (\varphi -{\varphi }_J{)}^{\beta }$ as measured on foams, emulsions, and colloidal systems and predicted by numerical simulations on hard spheres.

• Received 12 November 2003

DOI:https://doi.org/10.1103/PhysRevLett.92.258303