‘Terminator’ Movie Tech: Phase-Shifting Robot Can Switch Between Liquid and Solid States

The sea cucumber, sometimes referred to as the “headless chicken monster,” inspired researchers working on a shift-changing material. (NOAA Office of Ocean Exploration and Research, via AP)

Scientists have created a robot capable of turning into liquid and reforming back into its original shape, a development that can herald new applications in healthcare and other fields; but it has also triggered comparisons with the antagonist from the Terminator movies as the substance can be made in a humanoid shape.

The innovation, detailed in the journal Matter on Jan. 25, was inspired by sea cucumbers. Traditional hard-bodied robots are stiff and rigid, making them strong, stable, and easy to control. In contrast, “soft” robots are flexible but are weak and difficult to control. The new material solves this problem. “Giving robots the ability to switch between liquid and solid states endows them with more functionality,” Chengfeng, an engineer at The Chinese University of Hong Kong who led the study said in a news release.

In addition, these robots can also conduct electricity as they are magnetic. The research team is calling the new phase-shifting material used in the robots “magnetoactive solid-liquid phase transitional machine.”

The material was created by embedding gallium with magnetic particles. Gallium is a soft, silvery metal when under standard temperature and pressure. It has a low melting point.

In a video posted online, a humanoid model made from the phase-shifting material can be seen trapped inside a model prison. The humanoid melts and flows outside the prison, eventually reforming itself.

Many netizens are equating this demonstration with the iconic T-1000 terminator from the 1991 movie Terminator 2 which also displayed similar liquefying capabilities.

Better Phase-Shifting Material, Medical Application

According to senior author and mechanical engineer Carmel Majidi of Carnegie Mellon University, magnetic particles used in the phase-shifting material perform dual functions.

“One is that they make the material responsive to an alternating magnetic field, so you can, through induction, heat up the material and cause the phase change. But the magnetic particles also give the robots mobility and the ability to move in response to the magnetic field,” he said in the eurekalert.org news release.

There are some phase-shifting materials already in existence. But unlike the new material, these existing materials rely on electrical currents, heat guns, and other external heat sources in order to trigger the transformation between solid and liquid states.

Moreover, the new material is also said to be much more fluid in its liquid state when compared to other phase-shifting materials that tend to be more viscous when liquid.

The research team tested the material by subjecting it to a variety of tasks. This includes the terminator-style “prison break,” climbing walls, splitting in half to move objects by cooperating with each part before joining back, and jumping over moats.

The innovation can be very useful in healthcare. In one test, the team used the phase-shifting robot to remove an object from the model of a human stomach. A video of the test shows how the phase-shifting material moves the item out. In another test, the team delivered drugs into the model stomach.

Phase-Shifting Material Studies

Several studies are ongoing that research phase-shifting materials. In 2020, researchers from the University of Southampton in the UK showcased a phase-changing material that exhibited no loss of light at telecommunication wavelengths.

When compared to existing high-end optical materials, the new material showed 100 times less loss of light while also being capable of being switched with low power.

In 2021, scientists from the Embry-Riddle Aeronautical University’s Research Park in Daytona Beach, Florida, demonstrated the use of a phase-change material to create heat-exchange devices that can someday help buildings save on cooling costs.