According to foreign media reports, scientists at Carnegie Mellon University are developing a fluidic transistor based on indium gallium alloy material that is liquid at room temperature and is expected to open up a soft, natural mechanical engineering electronics . It can be used in areas of interest such as biocompatible disease surveillance, deforming robots, and even 'slimy' computers, etc. Heretofore, the example of liquid electronics has only one small bead of mercury, Close the switch between the wires.
Indium gallium alloys, which are liquid at room temperature, are expected to be used to create scalable circuit cabling and electrical switches (Photo: Carnegie Mellon University)
In contrast, liquid transistors fabricated with non-toxic alloy materials are much more complex structures, but we can implant it in rubber to create a soft, scalable circuit.
Figure 1: A Look at Liquid Metal Transistors
The mercury switch, described earlier, required tilting the glass tube to close the circuit, but the fluidic transistor developed by Carnegie Mellon researchers can turn the switch on and off by applying different voltages across the metal droplet.
When they flow in one direction, the combination of the droplets causes the circuit to close, and if they are in different directions, the droplets will separate and the circuit will be open, Carmel Majidi Two researchers James Wissman said:
Figure 2: Summary of droplet coalescence and separation behavior.
Due to the instability of capillary phenomena, it is possible to mimic the behavior of a transistor by simply turning the switch on and off alternately. The difficulty is induced instability, and then the drops merge into one seamlessly and seamlessly back .
We can always see the instability of the capillary, and if you turn on the faucet and the flow is low, you can sometimes see it change from a constant flow to a separate drop, a phenomenon known as Rayleigh instability (Rayleigh instability).
Figure 3: Gradient simulation of surface tension evolution
Majidi said: 'We can set two similar drops at the source and gate of the field-effect transistor to take advantage of this shape-programmable effect to turn the circuit on and off. Ultimately, we can use this effect to create these bodies Reconfigure the circuit '.
The researchers said the new fluid transistors open up new prospects for microcomputers, such as the biocompatibility that can be directly in contact with body tissues, enabling them to be used for disease monitoring and help stroke patients regain their brain function.In addition, liquid circuits allow The material is reconfigured to change its function or bypass the damaged area.
Figure 4: Results on droplet separation
Majidi adds: 'Structural changes can take place quite a lot, like a flying robot that mimics a bird, and when it spreads its wings, you want the circuits on the wings to be distorted and reconfigured to keep them or Support other types of electrical functions'.
Field-Controlled Electrical Switch with Liquid Metal has been published in the recently published Advanced Science journal.
