We normally think of robots as metal and plastic mechanical devices that range from children’s toys to those used in car manufacturing. Robots used in medicine can benefit from being built out of more biocompatible materials, so researchers at North Carolina State University have created a way to make hydrogels bend and fold in response to an electric current.
Hydrogels are made of water and hydrophilic polymer chains, but to activate them the researchers injected copper ions that bind with the negatively charged polymer molecules within the gel. The more ions are injected using an electric current, the stiffer the site becomes and the gel bends in on itself.
Here’s a lively video demonstration of the activated gels:
Paper in Nature Communications: Reversible patterning and actuation of hydrogels by electrically assisted ionoprinting