Engine with progress: a micromotor will deliver medicine anywhere in the body
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- Engine with progress: a micromotor will deliver medicine anywhere in the body
Russian scientists have created the world's first internal combustion micromotor as thick as a human hair. The device is capable of propelling objects exceeding its mass by a thousand times. The fuel for the motor is salt water, which under the action of electricity turns into hydrogen and oxygen. The gases are then ignited, producing an explosion that pushes the analog of a piston. The invention can be used for targeted drug delivery. For example, the micromotor could replace bulky insulin pumps.
The world's smallest internal combustion engine
Specialists of the Kurchatov Institute have developed for the first time in the world an internal combustion micromotor as thick as a human hair. The device is capable of propelling objects 1 thousand times its mass. As a fuel in the development uses salt water, which with the help of electricity is converted into gas. Then in the chamber of the engine there is a reaction of hydrogen combustion and explosion, which pushes the membrane, which acts as a piston. After that, the gas is again turned into a liquid, and the operation is repeated.
According to the developers, scientists have long been working on reducing the size of internal combustion engines, but as the volume of the chamber decreases, the combustion reaction begins to go out due to increasing heat losses. Now this fundamental difficulty has been overcome and the combustion reaction can be realized in a small volume.
- We produce hydrogen and oxygen from water by electrolysis. The bubbles expand and push the membrane, this principle is not new. It is important to quickly remove the gas afterwards, so that the actuator is triggered repeatedly, only then this engine can fully function, - said Ilya Uvarov, a senior researcher at the Yaroslavl branch of the K.A. Valiev Institute of Physics and Technology (from 2023 - as part of SIC Kurchatov Institute).
In the new device, feeding a special control signal to the electrodes creates a microbubble containing a mixture of hydrogen, oxygen and water nanodroplets under tremendous pressure. The latter are responsible for igniting the reaction between the gases, resulting in a 500-fold increase in the volume of the bubble in just 10 microseconds. In fact, an explosion occurs in the chamber, propelling the membrane with tremendous acceleration and therefore force. As a result, all the gas created burns off in a few nanoseconds and turns back into water.
According to the creators, the most obvious practical application of their development is to use it to push liquids through microchannels. For example, this could be a way to replace the rather bulky pumps now used to deliver insulin. However, just like conventional internal combustion engines, their micro analog can be used in any micromechanical devices. These are scaled-down versions of traditional equipment that are now becoming more and more in demand.
Attempts to create a micromotor are now being made all over the world. Electrostatic drive can be well miniaturized: two plates, to which voltage is applied and they are attracted to each other. But such a device has too little power. There is also an electromagnetic motor, but it is very difficult to reduce, since it has a voluminous construction of a coil, a magnet and other elements. Therefore, no one has been able to create a powerful and efficient micron-sized motor yet.
The trend towards miniaturization
Today miniaturization is one of the main trends in technology development, noted Alexey Karfidov, Head of the Department of Engineering of Technological Equipment at MISIS University. It is important from both scientific and applied points of view.
- It is always more difficult to make something in a smaller version than in a larger one. At the same time, such engines are usually designed for a specific application. Also important is the development characteristics, which must be correlated with the payload and functions of the required device. The more such complex products are created in our country, the better," he said.
The development deserves the attention of the scientific and engineering community, as the scientists have proposed an original energy converter (heat energy from combustion of hydrogen and oxygen is converted into mechanical motion) for micron devices for various purposes, said Leonid Plotnikov, professor of the Department of Turbines and Engines at the Ural Federal University.
If the solution will be cheap and accessible, it will definitely be in demand in robotics, especially when it comes to miniature devices, where it is still impossible to find long-running, efficient and relatively powerful motors especially for such a small size, emphasized Andrei Leus, a leading researcher at the laboratory of digital special-purpose systems at MIPT. If this technology is brought to an engineering solution, but remains quite expensive, it can still be applied in medical technology or research in the field of biology, he believes.
- The principle of action remotely resembles the operation of an internal combustion engine at micro- and nano-levels. The development of scientists can find application in many areas of miniaturized technology (in electronic devices, robots, etc.). The membrane microactuator is especially interesting and promising in the field of medicine, for example, its application for wearable and implantable devices (electronics)," he said.
Before entering the market, the development of scientists should prove its reliability, stability and stability of operation, as well as efficiency and competitiveness in comparison with analogs, the specialist emphasized.
