Teams of scientists from China and Australia, working independently, claim they have just made an important first step towards building a robot that can keep on functioning even if you fire a shotgun at it a few times, just as Arnold Schwarzenegger does in Terminator 2: Judgment Day.
The key to this unusual behavior of the new material is gallium, which becomes liquid at just under 30 °C. Add some indium and tin, mix well and you get “an intelligent drop”. Keep it in brine and feed in just a tiny flake aluminium and it will be going about for a full hour, doing all sorts of amazing tricks. For example, it is capable of moving in a straight line, run around a circular dish, or squeeze through complex shapes. Moreover, this flexible electronic material can automatically repair itself whenever it gets damaged.
But before recreating a T-1000 in our world, scientists needed to answer one big question and namely what makes the intelligent drop so agile. Some of the thrust, they have found out, stems from a charge imbalance across the drop, which in turn creates a pressure difference between its front and back that pushes the drop forward. The aluminum also reacts with sodium hydroxide (or brine), releasing hydrogen bubbles which propel the drop even faster.
It will be a while before the new material is used to make humanoid robots, but scientists have already found some immediate applications of the malleable stuff.
For example, it can be used to move liquids through cooling devices without the need for an external power source, monitor the environment or deliver materials within pipes and even human blood vessels.