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

¹  Department of Physics and Astronomy, University California-Los Angeles - Los Angeles, CA 90095, USA
²  Department of Chemistry and Biochemistry, University of California-Los Angeles - Los Angeles, CA 90095, USA
³  California NanoSystems Institute, University of California-Los Angeles - Los Angeles, CA 90095, USA

Corresponding author: mason@physics.ucla.edu

Received: 28 April 2008
Accepted: 30 May 2008

Abstract

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.