Arnie's Terminator 2 robot shapes landmark University of Wollongong discovery

UOW researchers have now realised the non-contact manipulation of liquid metal, after being motivated by the liquid metal robot in 1991 Hollywood movie Terminator 2.

"By combining electromagnetic induction and fluid dynamics, we were able to manipulate the liquid metal in a controllable way, and move like soft robotics," Senior Professor Xiaolin Wang explained.

"The research in liquid metals was inspired by biological systems as well as science fiction, including the shape-shifting, liquid metal "T-1000" robot in the James Cameron-directed film Terminator 2."

Prof Wang is a node leader and theme leader at the ARC Centre of Excellence for Future Low-Energy Electronics Technologies (FLEET), and led the research team from UOW's Institute for Superconducting and Electronic Materials within the Australian Institute for Innovative Materials.

"This research is more than science fiction, we have conceived and realised this non-contact method for liquids, offering a new way to manipulate and shape fluids."

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UOW PhD student Yahua He was lead author of the study, published in the January issue of Proceedings of the National Academy of Sciences of the United States of America (PNAS), one of the world's premier journals for multidisciplinary research.

"The non-contact manipulation of liquid metal allows us to exploit and visualise electromagnetism in new ways," Mr He said.

"The ability to control streams of liquid metals in a non-contact manner also enables new strategies for shaping electronically conductive fluids for advanced manufacturing and dynamic electronic structures."

To date, free-flowing liquid streams have been particularly difficult to manipulate in a non-contact manner.

Realising highly controlled changes in directionality or complex shaping of liquids, especially without disrupting the cross-sectional shape of the stream, was the challenge for the team at UOW.

"Once the team started working on this topic, we realised that there is much more behind it," Professor Wang said.

"The liquid metal wires form by applying a small voltage (approximately 1 volt). However, our team found that a considerable electrical current (up to 70 mA) could be measured in the resulting wires.

"There was a creative leap at this point, as the team realised that electromagnetic induction could be used to control the liquid metal wires in a non-contact manner. This was the key to finally successfully solving the challenge, thereby developing a new strategy for shaping fluids in a non-contact manner."

This non-contact manipulation is made possible by the material's unique fluid dynamic and metallic properties. As soft, current-carrying conductors, the wires present minimal resistance to manipulation via Lorentz force under a controlling the magnetic field. Thus, the researchers could manipulate the wires in designed ways.

Co-author Professor Michael Dickey from North Carolina State University said this very low resistance to movement allowed unusually fine control of resulting shapes.

"Usually, liquid streams break up into droplets. However, the liquid metal wire has a string-like property, similar to waving ribbons in the air. That property allowed us to manipulate the liquid metal stream into continuous loops and other shapes," he said.