A metal robot that can flow

  In the movie “Terminator 2: Judgment Day” released in 1991, there was a war between robots and humans in the future. In order to stop the human leader Connor, the supercomputer “Skynet” sent the robot T-1000 to travel from the future to 20 At the end of the century, he pursued and killed Connor as a teenager. At the same time, the adult Connor also sent the robot T-800-the robot hero played by Arnold Schwarzenegger went back to the past to protect his young self. The battle began.
  I believe anyone who has watched this movie will be impressed by the villain robot T-1000 in the movie. It can be transformed into any shape at will, and after being hit by a bullet or melted, it can be restored again, which is incredible.
   Now, robots like T-1000 will no longer be a myth, it may become a reality! Scientists have discovered a simple composite liquid metal that can “eat fuel”, move on its own and change shape. Therefore, researchers named it liquid metal mollusk. Although there is still some gap with the humanoid T-1000 in the movie, it paves the way for the future of liquid metal robots.
   Broad prospects liquid metal
   Speaking of liquid metal, many people first thought is mercury, which is metallic mercury, it is the only single metal in the liquid state at normal temperature and pressure. Because mercury can evaporate at room temperature, and mercury vapor and mercury compounds are highly toxic, people once had a deep stereotype of liquid metal, which hindered people’s attention to liquid metal.
   In fact, in addition to mercury, there are many alloys that are also liquid at room temperature or even very low temperatures, such as gallium indium alloy (alloyed with a certain ratio, it will be liquid at room temperature). Compound liquid metal, especially gallium-based liquid metal is now regarded as a future material. It not only has the excellent conductivity of solid metal, but also can flow freely like water, and it can be adjusted artificially (changing the metal composition and ratio). Etc.), which can be optimized materials with different properties, thus having broad application prospects in many fields such as industry and medicine.
   The first to introduce liquid metal into the industrial field is the problem of computer heat dissipation. With the development of modern technology, the computing speed of computers is getting faster and faster, and higher computing speed means more heat. Therefore, the heat dissipation of computers has become a difficulty hindering the development of computer chips. The thermal conductivity of liquid metal is very high, which can achieve more efficient heat transport and has the ultimate heat dissipation capacity. In particular, the boiling point of liquid metal is around 2000°C and can withstand very high temperatures without being vaporized.
   In addition, people can also use liquid metal to print metal circuits to achieve rapid circuit manufacturing. Here is an anecdote. At that time, in the research team led by Professor Liu Jing of Tsinghua University, once, liquid metal splashed on the researcher’s computer screen, and as a result, some metal remained on the computer screen and could not be wiped off. The researchers found that there are huge differences in the adhesion of liquid metal materials on different substrate surfaces. When the liquid metal is coated on a specific substrate surface, when the adhesion is great, it will be fixed on it, and we can print any pattern at will.
   Finally, liquid metal can also be used in the medical field to connect damaged nerves. Neural networks are all over the body, and nerve damage and breakage are extremely common in medicine. At present, the main method to treat peripheral nerve injury is autologous nerve transplantation, but this method is limited by insufficient source of donor nerves, loss of donor nerve function, and mismatch of donor nerve structure and size. Therefore, finding suitable nerve graft substitutes has always been a major challenge in the field of nerve repair.
   Since the function of nerves is mainly achieved through the transmission and response of electrical signals, using liquid metal as a highly conductive nerve signal pathway can enable the continuous transmission of nerve signals between neurons and greatly accelerate the process of nerve repair.
   Flexible robot
   After understanding the magical liquid metal, let us return to the opening topic-flexible robots. The so-called flexible robot refers to a deformable robot that can freely and controllably convert between different forms. Since liquid metal is an amorphous metal, it can be regarded as a mixture of positive ionic fluid and free electron gas. Researchers at the University of Sussex in the UK used an external electric field to control the arrangement of charges in the liquid metal, thereby controlling The shape of the liquid metal is not fixed by the applied electric field and can be changed at any time through a computer program, so researchers can flexibly control the shape and movement of the liquid metal.
   However, the artificial control of liquid metal is not surprising. What really surprised us was the liquid metal mollusk, which can “swallow” metal aluminum and then keep it in motion for 1 to 2 hours. In fact, when metallic aluminum and gallium-based liquid metal are in contact, the electrons in metallic aluminum flow to the gallium-based alloy, causing differences in charges at different parts of the alloy, and causing the movement of the liquid metal. Moreover, the liquid metal in the experiment was placed in a sodium hydroxide solution. The aluminum “eaten” by the liquid metal would also react with the solution to produce hydrogen gas, which further promotes the movement of the liquid metal.
   In the laboratory of Professor Liu Jing of Tsinghua University, the researchers found that in the pre-designed metal movement pipeline, the liquid metal mollusk can change its shape according to the size and direction of the pipeline, which really allows scientists to see the flexible metal The future of robots. Because the liquid metal mollusk does not need any external electric field, it is completely autonomous. This provides scientists with a new idea. The flexible metal robot can finally get rid of the shackles of the electric field and become more free. If you continue to study in this direction, it is possible to realize a metal robot like T-1000.
   Of course, all scientific research is inseparable from the promotion of practical applications. Thanks to the deformable characteristics of liquid metal, in the future, liquid metal robots can be used for special tasks, such as searching and rescuing earthquake victims, because they can change their shape, slide under doors, and enter spaces inaccessible to humans. Moreover, scientists are also actively researching flexible robots that move along blood vessels or cavities to help humans clean blood vessels or intestines, etc., “by the way” can also be used for drug delivery and minimally invasive surgery.