The Japanese have created a hydrogel that works as an artificial muscle.

Researchers from the Japanese institute RIKEN created a hydrogel , which changes its shape depending on temperature. In this case, the structure of the gel makes the deformation directed - it significantly changes its linear dimensions only in one direction. The amount of liquid absorbed by the gel during such deformations remains constant.


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Conventional hydrogels are known for being able to absorb a large amount of liquid, several times their own weight. Absorbing the liquid, they evenly increase in volume, and to decrease, they need to give it away. And this process takes quite a long time.

The unusual hydrogel obtained by the Japanese works like an artificial muscle . As the temperature increases, it significantly stretches in one direction, and slightly shrinks in the other, keeping the original volume. The square sample becomes rectangular, and the corner made by scientists from this material walked cheerfully on a flat surface.



When creating the material, previous developments of scientists were used, in which they coagulated the polymer into a hydrogel using light, and created thin films of metal oxide using magnetic fields. This material consists of a multitude of layers of nanofiber, held together by a polymer, between which electrostatic repulsion forces act. As a result, as the temperature rises, repulsion begins to predominate, and the material expands in one direction, increasing the distance between the layers.

Yasuhiro Ishida, one of the researchers, explains that scientists sought to create a material that expands in one direction, but at the same time its properties such as volume preservation and ability to work without liquid, in air, came as a surprise to them. It exceeded expectations and high strain rate, which is about 70% of the length per second.

While scientists conduct further research in this area. Such material can be used as artificial muscles, for example, in any valves, which should quickly work when the temperature changes.