Spider silk is already known as one of the strongest materials for its weight, but researchers discovered an unusual property of the material that could make it useful in robotics. Its “supercontraction” could lead to the creation of new types of artificial muscles.
Spider Silk Robot Muscles
A team of researchers discovered a property of spider silk called “supercontraction” wherein the fibers of spider silk shrink in response to moisture changes. When it happens, the fibers don’t just contract but also twist, thereby providing strong torsional force.
On its own, spider silk is already known as one of the strongest materials, with incredible strength-to-weight ratio, resilience, and toughness. Although the researchers are unsure as to how supercontraction is used by spiders, this discovery could lead to the creation of silk-based materials that behave in response to humidity, or it may also be replicated in synthetic materials to replicate the behavior.
“Potential applications are diverse: from humidity-driven soft robots and sensors, to smart textiles and green energy generators,” said Anna Tarakanova, assistant professor at the University of Connecticut and coauthor of the paper.
Particularly of interest are its potential applications for the robotics community. Evidently, the material’s behavior may be exploited to create artificial muscles that can be precisely managed by controlling the humidity.
Interestingly, the researchers merely made the initial discovery by accident. During an experiment, they tied a weight to the end of spider silk and created a pendulum inside a chamber where they could control the humidity. When they increased the humidity, the pendulum started to rotate.
The researchers looked into other materials such as human hair that could possibly have this property, but none of the materials they tested exhibited the twisting property. That said, they surmise that it is possible for other natural materials they have yet to test to have this property as well.
The study is published in the journal Science Advances.