An unexpected shape formed when a graduate student accidentally blended oil, water and nickel. Scientists discovered that the shape-recovering liquid defied the laws of thermodynamics. Instead of minimising the interfacial area and turning into a sphere, the mixture of liquid took the shape of a Grecian urn. This research was conducted by a team led by a graduate student, Anthony Raykh, at the University of Massachusetts Amherst; the findings were published on April 4 in the Journal Nature Physics.

The Accidental Discovery

As per the study, Raykh, a student of polymer science and engineering, was experimenting with a jumble of water, oil and nickel particles in a container. To create an emulsion, he shook the vial. The mixture didn’t get separated as it should have, instead, it formed the shape of a Grecian urn. Even after shaking the mixture multiple times, the liquid kept returning to this shape. Thomas Russell, a professor of polymer science and engineering, told Live Science that this is an odd behaviour of the particles. It is quite strange because such a mixture doesn’t blend, and it returns to the state of equilibrium.

A Challenge to Thermodynamics

The blend tends to reduce the line of separation or interfacial area between the two liquids before emulsion. The law of thermodynamics governs this tendency, showing how temperature, work, heat and energy relate to each other. The liquid generally forms spherical droplets, having a minimum surface area. In contrast to this, the Grecian urn has a higher surface area, contradicting the law of nature, baffling the scientists.

Magnetic Interactions Take Over

After the investigation of this strange behaviour of the particles, they found that the interactions between the particles of nickel “sort of took over” and defied the law of thermodynamics, Russell says. The magnetic poles of the particles attracted each other, making a chain on the surface of the liquid. This interaction intersects with the phenomenon of emulsion of the liquid. Russell told the researchers have examined the separation of the particles in an oil-water blend. But in contrast to this, Raykh had added nickel to the mixture, which nobody else did. Thus, none had observed the shape of the Grecian urn with higher interficial energy.

A Strange Case, Not a Violation

Initially, this seemed to challenge the law of thermodynamics, but Russell clarified that this is a strange behaviour of the particles due to the magnetic field. This magnetic field influenced a high interfacial energy, which resulted in the formation of a higher surface area shape.
Russell says the law of thermodynamics applies to the system as a whole and not just based on interactions between the individual particles.