Title: Capillary breakup rheometry of shear-thickening suspensions

Author (Talk): Pawel Zimoch, MIT

Abstract:

The behavior of shear-thickening suspensions in extensional flows has not been investigated as thoroughly as their behavior in shear flows. This is partly due to experimental problems such as gravitational draining associated with traditional methods of creating extensional flows. We present a new method of performing capillary breakup experiments on shear thickening suspensions which relies on placing a thin, horizontal layer of a suspension between two layers of oil. While limiting gravitational draining, this method also allows for direct visualization of microstructure just before pinch-off. Experiments performed on suspensions of corn starch and silica particles show unexpected phenomena such as formation of satellite and sub-satellite droplets linked together by thin threads.