Shear oscillation light scattering of droplet deformation and reconfiguration in concentrated emulsions

Large strain-amplitude oscillatory shear flows can cause significant structural changes in concentrated suspensions of deformable colloidal spheres that have volume fractions exceeding the quiescent jamming limit of hard solid spheres. In contrast to hard spheres, which can jam, lock-up, and even break fixed-gap shearing devices, droplets can readily deform and remain lubricated. By introducing shear oscillation light scattering, we explore how shear-induced droplet deformation facilitates un-jamming, ordering, disordering, and re-jamming of uniform concentrated droplets as a function of the amplitude, frequency, and phase of an applied oscillatory shear.