How to Fracture a Fluid

W hat does it take to fracture a fluid? How hard and fast does the fluid need to be pulled in order to break? Ole Hassager, from the Technical University of Denmark, and colleagues [1] have tackled these challenging questions head-on by stretching fluids composed of polymer melts at sufficiently high strain rates to make the fluid break in the same way that a pane of glass would if pulled hard enough. The researchers found that as long as the strain rate was fast enough, fracture of the fluid followed. The overall strains that the fluids could sustain before breaking were both huge—over 250% of their initial size—and surprisingly reproducible.