Shock-driven jamming and periodic fracture at particulate interfaces

A tenuous monolayer of hydrophobic particles at the air-water interface often forms a scum of raft. When such a monolayer is disturbed by the introduction of a localized surfactant droplet, a radially divergent surfactant shock emanates from the origin of the surfactant 
and packs the particles into a jammed compact annular band that grows with time. The resulting two-dimensional, disordered, elastic solid locally has a packing fraction that saturates and fractures as it is driven outwards radially, to form periodic triangular cracks with robust geometrical features. I will describe a very simple experiment complemented by a minimal molecular dynamics simulation that studies the formation and failure of a disordered solid at the air-water interface