The joint team recently published a paper in Advanced Materials magazine, announcing the first discovery in the world that liquid metal has an extremely unique phenomenon and mechanism, that is, liquid metal can move at high speed for a long time in the form of a deformable machine after swallowing a small amount of substances.
Professor Tsinghua University, the head of the group, and Liu Jing, a double-hired researcher at the Institute of Physical and Chemical Technology of the Chinese Academy of Sciences, said that the experiment found that gallium-based liquid alloy placed in the electrolyte can provide energy by "ingesting" aluminum as fuel, which can run at high speed, high efficiency and for a long time: only a small piece of aluminum is needed, and a liquid metal ball with a diameter of about 5 mm can be driven to complete the continuous movement of 1 hour or more, with a speed of 5 cm/second. ..
"Interestingly, we have observed that this deformation machine can not only move in free space, but also move forward in various structural channels. What is even more surprising is that it will adjust itself according to the width of the channel, and it will pause when turning, as if people are traveling after encountering obstacles, just like the liquid robot in the sci-fi movie Terminator. " Liu Jing said.
Liu Jing and his research team affectionately call this liquid metal machine "mollusk" because it presents a series of unusual features, which are quite close to the simple mollusk in nature.
The research team made different sizes of liquid metal machines in the laboratory, ranging from tens of microns to several centimeters, and verified their autonomous motion performance in different electrolyte environments such as alkaline, acidic and even neutral solutions.
The researchers also revealed the main sources of power for this autonomous liquid metal machine: first, the endogenous electric field formed by liquid alloy and metal fuel induces the asymmetric response of high surface tension on the liquid metal surface, thus bringing powerful thrust to the deformed liquid metal machine; Secondly, the hydrogen generated in the above electrochemical reaction process further provides thrust for the movement of liquid metal.
Liu Jing's research group has been devoted to the research of liquid metal. In 20 14, this group discovered for the first time in the world that the complex of liquid metal and water can be transformed between various forms and motion modes under the control of electric field. On this basis, through experiments and an accidental study, it is found that liquid metal is self-changing. Liu Jing said that liquid metal, as a new functional material, has many novel physical properties that conventional materials do not have, and the in-depth study of it can provide rich research space for materials science.