Through the development of three-dimensional printing technology and techniques, researchers from North Carolina State University have discovered a way to create free-standing structures made of liquid metal at room temperature.
"It's difficult to create structures out of liquids, because liquids want to bead up. But we've found that a liquid metal alloy of gallium and indium reacts to the oxygen in the air at room temperature to form a 'skin' that allows the liquid metal structures to retain their shapes," Michael Dickey, an assistant professor of chemical and biomolecular engineering at NC State and co-author of a paper describing the work, said in a press release.
Throughout the study, the researchers developed multiple techniques for creating these structures that can be used to connect electronic components in three dimensions, including stacking droplets of liquid metal on top of each other like a stack of oranges at the supermarket, they said. Importantly, the droplets adhere to one another, but retain their shape, withstanding the urge to merge into a single, larger droplet.
Another technique injects liquid metal into a polymer template so that the metal takes on a specific shape before the template is then dissolved, leaving the bare, liquid metal in the desired shape.
Furthermore, the researchers developed techniques for creating liquid metal wires able to retain their shape even when held perpendicular to the substrate.
Going forward, Dickey's team is exploring how to further develop these techniques, as well as devising ways to use them in a variety of electronics and with current 3-D printing technologies. However, despite the fact that Dickey oversaw the work, the main driving force, he says, was someone else entirely. "I'd also like to note that the work by an undergraduate, Collin Ladd, was indispensable to this project," Dickey says. "He helped develop the concept, and literally created some of this technology out of spare parts he found himself."