Scientists have obtained a self-propelled drop of liquid metal

Chinese scientists from Tsinghua University in Beijing have obtained a self-propelled drop of liquid metal, which uses aluminum chips as fuel. A drop can move in a straight line, circumferentially around a saucer, or pass through complex mazes.



Jin Liu, one of the researchers, says: “This non-rigid machine looks like a living one. She can change the shape according to the place she went, just like the Terminator from a science fiction film. This unusual behavior is very much like the actions of living organisms in nature. " Liu believes that this experiment even raises the fundamental question of determining what life is.



The mechanism of motion of the drop was discovered by chance. The drop consists mainly of gallium with impurities of indium and tin. At a temperature of 30 degrees this mixture is in the liquid phase. If you put it in sodium hydroxide, or even just in salt water, and “feed” a piece of aluminum to it, it starts moving. Part of the driving force is caused by the difference in electrical potentials arising from the reaction with aluminum. In addition, the interaction of aluminum with sodium hydroxide releases hydrogen bubbles, which, like a jet engine, push a drop forward.

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If, on the contrary, to fix the drop in place, it begins to work like a pump. As a result, the drop pumps up to 50 milliliters of water per second. Thus, the drop works as a pump without an external power source.



Interestingly, scientists are just working on the creation of non-rigid robots that would be able to work in difficult conditions and deliver a variety of materials in confined spaces, up to the bloodstream.







Last year, both Chinese and American scientists found that gallium can be made to take various complex forms by acting on it with an electric current. As a result, the surface tension of the metal changes, which leads to a change in the shape of the droplets. Liu believes that by combining these two methods, you can control the speed of the drops or coordinate the work of a whole group of independent drops.