Interfacial jamming phenomena in ternary liquid/liquid/solid systems

Friday, April 13, 2012 – 12:00pm
Reiss 261A
Sachin Velankar
U. Pittsburgh

Particles that are partially wetted by two immiscible fluids can adsorb at the interface between the fluids. The energy for desorption is usually large, and hence the adsorption is nearly irreversible. Thus at sufficiently high surface coverage, the particles can jam the interface giving it solid-like properties. We will explore such two-dimensional jamming using a spinning drop tensiometer and relate the phenomenology of jamming to conventional glass formation in two dimensions. We will review the consequences of jamming in ternary liquid/liquid/solid systems such as Pickering emulsions, bijels, or particle-stabilized foams. These consequences include the stabilization of non-spherical drop shapes, anisotropic morphologies in emulsions, and the gel-like rheology of ternary systems. Finally we will discuss unique emulsion morphologies in which particles glue together drops by bridging across a thin film of continuous phase. The talk will conclude with a discussion of some applications of particle adsorption for controlling the structure of oil/water emulsions, polymer blends, and foams.