Liquid filament instability due to stretch-induced phase separation in polymer solutions: Liquid filament instability.

The instability in a jet of a viscoelastic semidilute entangled polymer solution under high stretching is discussed. Initially the jet is stable due to solution elasticity stopping the fluctuation growth. The modeling shows that a jet stretching results in a radial gradient in the polymer distribution: the polymer is concentrated in the jet centre, whereas the solvent is remaining near the surface. This viscous liquid shell demonstrates Raleigh-type instability resulting in the formation of individual droplets on the oriented filament. All process stages were observed experimentally.