Deformation, restructuring, and un-jamming of concentrated droplets in large-amplitude oscillatory shear flows

We employ large-amplitude shear oscillation light scattering (SOLS) to study average droplet deformation and positional restructuring in concentrated uniform oil-in-water emulsions. Three dimensionless scattering intensity anisotropy factors, defined using the primary and secondary Bragg peaks, which can result from partial shear-induced ordering, reflect the phase-dependent droplet deformation and tilting. These factors distinguish the soft force-chain buckling regime, where shear disorders the droplets, from the sliding hexagonally-close-packed layer regime, where shear induces positional order. Near and above the jamming limit of spherical particles, the shear-induced structures depend sensitively on the droplet volume fraction and the shear history.