Drexel University Researchers Rewrite Fluid Physics as Stretching Liquids Snap Like Brittle Solids

Drexel University scientists find that liquids can fracture like solids under extreme stress, a discovery that rewrites the rules of fluid mechanics.

By: AXL Media

Published: Mar 30, 2026, 11:13 AM EDT

Source: Information for this report was sourced from Drexel University

A Fundamental Shift in Understanding Liquid Behavior

The established laws of fluid mechanics have long dictated that simple liquids, such as water or oil, will continuously thin and flow when pulled apart. However, researchers at Drexel University’s College of Engineering have upended this principle by capturing "brittle fracture" in viscous liquids. The study suggests that viscosity—the internal friction of a fluid—plays a far more mechanical role than previously recognized. According to Assistant Research Professor Thamires Lima, any simple liquid pulled with sufficient force per area will eventually reach a breaking point, fundamentally altering the scientific approach to fluid dynamics.

Unexpected Discovery During Routine Rheology Testing

The phenomenon was first observed during an extensional rheology test involving tar-like hydrocarbon blends conducted in partnership with ExxonMobil. Rather than stretching into thin filaments like honey, the liquid specimens suddenly snapped, producing a sharp noise that initially led researchers to believe their equipment had failed. High-speed cameras confirmed that the liquids were undergoing a fracture process nearly identical to that seen in metals or glass under stress. This serendipitous observation shifted the focus of the lab toward a completely new area of physical inquiry.

Viscosity as the Driver of Solid-Like Fracture

While fracture has traditionally been associated with elasticity—the ability of a material to store and withstand stress—simple liquids do not typically possess this trait. The Drexel team found that by adjusting the temperature and viscosity of styrene oligomers, they could trigger a fracture at a consistent "critical stress" of 2 megaPascals. This suggests that the snap is not dependent on the chemical makeup of the liquid but is instead a universal mechanical response tied to viscosity. At lower viscosities, the liquids could not be snapped only because existing machinery was unable to stretch them at the requisite speeds.