Rearrangement of 2D aggregates of droplets under compression: signatures of the energy landscape from crystal to glass

We study a signature of the energy landscape through the crystal-to-glass transition by compressing 2D finite aggregates of emulsion droplets. Oil droplets of two distinct sizes are used to compose small aggregates in an aqueous environment. Aggregates range from perfectly ordered monodisperse crystals to disordered bidisperse glasses. The aggregates are compressed between two parallel boundaries; crucially, one of the boundaries acts as a force sensor. The compression forces provide a signature of the aggregate composition and give insight into the energy landscape. In particular, crystals dissipate all the stored energy through single catastrophic fracture events whereas the glassy aggregates break step-by-step. Remarkably, the yielding properties of the 2D aggregates are strongly impacted by even a small amount of disorder.