Dynamic and structural investigation of capillary suspensions with smooth and rough particles

Capillary suspensions consist of particles suspended in a bulk fluid with a small amount of immiscible secondary liquid added to form a percolating network of capillary bridges between the particles and can show a wide range of rheological behavior. We investigate the microstructural changes during interesting rheological transitions, e.g. yield, using confocal microscopy. Using a rheometer mounted to a confocal microscope, we are able to directly investigate the yielding of a capillary suspension network subjected to a shear deformation. These experiments show the solid body rotation present in capillary suspension networks where flocs move as single objects, as well as very localized bridge rupture and reformation events