Hydrogel actuators are made stronger and faster by combining turgor and electro-osmosis.

Researchers at Seoul National University have created a faster and stronger hydrogel actuator using turgor design combined with electro-osmosis. The group explains their method and the performance of the actuator in their article published in Science. Zhen Jiang, from the University of Southern Queensland and Pingan Song comment in a Perspective piece published in the journal on the challenges researchers faced when trying to develop hydrogels which mimic biological organisms.

As their name implies, hydrogels are gels with a base of water. Since several years, roboticists have studied them in depth. Soft actuators are components that can be deformed to interact in desired ways with the environment. The actuator must be able convert energy into mechanical work in a similar way to the muscles of humans. Scientists would like to make the actuators more useful by increasing their actuation force and making them respond faster to the needs of the moment. Researchers have made a new step towards achieving these goals with this effort.

The team used standard techniques to create a hydrogel, but then wrapped it in an osmotic, stiff wrapper. The stiffness of the material was created to prevent a swelling as liquids entered into a turgor-cell structure. The pressure built up and exerted force on nearby objects. The cell was tested and it produced enough force (730 N), to split a standard building brick. Researchers note that this force is approximately 1,000 times higher than any other hydrogel. To speed up the action the researchers used an electric current that increased the speed of the actuation to 19 times the normal osmotic speed.

Source:
https://techxplore.com/news/2022-04-combining-turgor-electro-osmosis-strong-fast.html