Collapse of a granular raft: a single particle perspective

Particle-laden interfaces are interesting composite systems due to their potential application in emulsion stabilization, drug delivery, handling of hazardous materials. When the particles are heavier than the liquid phase and non-Brownian in nature, they self-assemble on the interface via capillarity to form granular rafts. In recent work, we experimentally observed that the bi-axial compression of the granular raft leads to two distinct modes of failure: collective creasing versus single particle expulsion, as a function of the particle size and the density difference between the upper and lower fluids. Despite the success of a barebones continuum model to describe our experiments, the connection between the single particle behavior and the raft failure is missing from our understanding. By combining new visualization experiments and modeling, we aim to uncover the connection between the position of the individual particle on the interface and the raft's macroscopic response to compression.