Researchers at the National Seoul Institute of South Korea created the simplest robots that do not require batteries and electricity for movement. They are able to move, twist, tumbling and move in different directions, using for this purpose moisture absorbed from the environment.
The developers were inspired by the example of plants that can draw moisture from air and land, changing shape and length, depending on the situation. Some plants fold their leaves when moisture is sufficient, but they can also dissolve them if they lack food.
Designed by Korean engineers, robots are not made from plant materials, they simply mimic the mechanisms of plants. The idea of developers is that for such bots moisture can become a natural source of energy. In addition, this method is non-toxic, in contrast to batteries, the creation of which often uses poisonous substances that can seriously pollute the environment. Moreover, if these robots are reduced even more, they can be used inside the human body for drug delivery, for example.
The hydrobots consist of two layers made of nanofibers. One of them absorbs moisture, and the other does not. Once the bot hits the wet surface, the absorbent layer swells, causing it to shrink. It is necessary to dry the layer as the bot returns to its original position. Repeating these cycles allows the bots to move and move independently.