New research suggests ice becomes slippery when contact disturbs the alignment of molecular dipoles in its surface layer, producing a disordered, liquid-like film. Saarland University simulations, reported in Physical Review Letters, argue this dipole-driven mechanism can operate even at very low temperatures where melting from pressure or friction is implausible. The result is based on computer models and will require experimental confirmation, but it shifts attention from mechanical heating to microscopic electrical interactions.
Why Ice Is Slippery: New Study Points to Molecular Dipoles — Not Pressure or Friction
New research suggests ice becomes slippery when contact disturbs the alignment of molecular dipoles in its surface layer, producing a disordered, liquid-like film. Saarland University simulations, reported in Physical Review Letters, argue this dipole-driven mechanism can operate even at very low temperatures where melting from pressure or friction is implausible. The result is based on computer models and will require experimental confirmation, but it shifts attention from mechanical heating to microscopic electrical interactions.
08:31 PM, 11/18/2025Science
Why ice may be slippery even when it can't melt
Most of us learned that ice is slippery because pressure or friction melts its surface, producing a thin film of water. But that explanation struggles to account for slipperiness at temperatures far below freezing. A new computational study from researchers at Saarland University offers a different mechanism: electrical interactions between molecular dipoles in ice and whatever touches its surface.
The dipole-disruption idea
Water molecules have partial positive and negative charges and so behave like tiny dipoles. When water freezes, those dipoles arrange into a crystal lattice with a preferred orientation. The team published simulations in Physical Review Letters suggesting that when an object—say, a shoe sole or skate blade—contacts the ice, it disturbs the arrangement of dipoles in the topmost layer.
"In three dimensions, these dipole–dipole interactions become 'frustrated,'" said Martin Müser, one of the study authors. That frustration, the researchers argue, disorder the top layer and can produce a liquid-like film.
Crucially, this effect is not driven by mechanical heating or pressure alone. The simulations show the dipole-driven disorder can occur even at extremely low temperatures where conventional melting is impossible. At those extremes the emergent film would be far more viscous than ordinary water—more like honey—so it would not necessarily be as slick as a thin water film at higher subzero temperatures.
Context and caveats
Ice is more complex than it looks: estimates of distinct ice phases range from a few dozen to many thousands, and scientists only recently identified new crystalline forms (for example, Ice XXI). That complexity helps explain why basic questions about ice still prompt debate.
Importantly, the Saarland result comes from advanced computer simulations, which provide a plausible microscopic mechanism but are not the final word. Experimental confirmation will be needed to test how strong and widespread the dipole-driven effect is under real-world conditions and how it compares with pressure- and friction-based explanations.
Bottom line: The new work reframes slipperiness as possibly rooted in microscopic electrical interactions rather than solely mechanical melting. If confirmed experimentally, it would change how we think about contact with ice across a wide range of temperatures.