Scientists at RMIT University in Melbourne, Australia have developed a technique for enabling liquid metals to move and arrange themselves autonomously in response to varying external conditions. The resulting electronics aren’t just soft and free-flowing, but are highly reconfigurable as well.
The team, led by Kourosh Kalatar-zadeh, says the work could help dynamic elastic electronic components that move autonomously to create new circuits, rather than be stuck in the one arrangement.
They unveiled their apparatus in Nature Communications.
While the liquid metal T-1000 from the Terminator franchise is still well and truly in the realm of science fiction, Kalatar-zedah and his colleagues wondered if they could borrow its fluidity and shape-shifting qualities to create electronic circuits.
Alloys of gallium are ideal candidates: the liquid metal is malleable and conductive. Could the researchers manipulate gallium alloys easily without touching them?
First, they popped droplets of the alloy galinstan (a portmanteau of gallium, indium and stannum) in water and adjusted the water’s pH and salt concentration to see how the galinstan droplet reacted.
They found the edges of the droplet deformed inwards in an acidic bath and bulged outward in a base. Adding sodium chloride, or plain old table salt, to the mix increased the bulging.
Using hydrogen chloride as the acid, sodium hydroxide as the base and salt, they produced switches and pumps by propelling galistan droplets around in fluid-filled tubes.
Importantly, galinstan is non-toxic – it’s commonly used in thermometers today.
One day, this work may form the basis for 3-D electronic displays and components that form and disassemble on demand.
And Kalantar-zadeh doesn’t discount the idea of building a 3-D liquid metal humanoid, such as the T-1000, one day – “but,” he adds, “with better programming”.