What's the future going to be like? No one really knows. But if scientists were to be asked, it's highly likely going to include metal that shifts shapes.
In a study published in the Proceedings of the National Academy of Sciences, a group of researchers from the North Carolina University outlined a method that let the shape of liquid metals be controlled by manipulating surface tension.
Carried out by Mohammmad Rashed Khan, Collin B. Eaker, Edmond F. Bowden, and Michael D. Dickey, the study used liquid metal alloys and shocks of low-voltage electricity to achieve the reported result.
Specifically, a gallium-indium liquid metal alloy was formulated for its high level of surface tension. Less than a volt of electricity was then applied to the metal alloy while it was immersed in water, resulting in an oxide layer around the alloy. This "skin" reduced surface tension between the water and the alloy, allowing the alloy to change in shape from a spherical blob to something akin to a pancake because of gravity.
In addition, researchers also found that changing charge polarity from positive to negative will reverse the effect of the charge on the alloy. With surface tension going back to normal, the alloy also goes back to its original shape.
"The resulting changes in surface tension are among the largest ever reported, which is remarkable considering it can be manipulated by less than one volt. We can use this technique to control the movement of liquid metals, allowing us to change the shape of antennas and complete or break circuits," said Dickey.
The discovery may revolutionize how circuits and electronics are made but manipulating surface tension in liquid metal may also be applied in the medical field, helping repair damaged nerves in people to prevent long-term disability.
Last year, scientists from the aerospace engineering and mechanics department of the University of Minnesota were able to create a shape-shifting metal alloy as well that can withstand heat blasts and immediate cooling thousands of times.
Martensite is a special form of metal with a crystalline structure. It can be bent and crumpled numerous times but it will always go back to its shape. Unfortunately, martensite will degrade after a while.
The University of Minnesota researchers improved martensite by adding copper, cold, and zinc, creating a metal alloy in the process. This metal alloy retains all the pliability of martensite but is dramatically sturdier, able to withstand 16,000 thermal cycles with very little degradation.
At the rate scientists are going, by this time next year, it's not so surprising to expect that more advancements in metal will be revealed.
