Viscoelastic effects probed by drop-jet collisions

We experimentally probe the stability of a continuous liquid jet deformed by successive impacts of immiscible drops. For Newtonian jets, two fragmentation thresholds are observed, which can be associated to two critical jet extensions. For viscoelastic jets, however, these fragmentations are partially or totally suppressed and cannot be correlated to any critical jet extension. We explain this dramatic change by the different drainage dynamics of the produced filaments, which we successfully model for both the Newtonian and viscoelastic jets. For the latter, long-lived filaments made of the jet liquid appear, which connect the encapsulated immiscible drops, giving rise to a new structure called Capsules On A String (COAS).