Geckos are really, really good at one thing in particular – running all around, even upside down, even when everything is wet.
Now scientists have created a double-sided adhesive that copies this ability to stick and unstick to slippery surfaces, and are looking at using it for underwater robots (presumably because underwater robots are exceedingly cool) but there’s another potential use, too.
Previously scientists have made a number of adhesives that can stick and unstick with changes in temperature, light or magnetic field – but mostly in dry conditions.
One approach to expanding this to underwater scenarios involves hydrogels, that can swell and shrink in response to different acidity levels and other conditions. These volume differences change the gels’ friction and stickiness levels.
Feng Zhou, Daniele Dini and team recently developed a method to integrate nanostructured hydrogel fibers on an inorganic membrane. The material’s friction and stickiness levels changed with pH even when wet. The researchers wanted to further expand on this strategy to make the adhesive work on two sides.
The researchers first made the inorganic membrane double-faced and then added the hydrogel nanofibers on both sides. Testing showed that the material exhibited ultra-high friction and adhesion in an acidic liquid (pH of 2), and would rapidly switch to a state of ultra-low friction and stickiness when a basic solution (pH of 12) was added. Additionally, the two sides of the material can stick and slide independently of each other.
“Underwater robotics, sensors and other bionic devices” have been highlighted by the researchers as possible uses. My bet is on us all gaining gecko climbing powers one day, in the glorious future, not too far from now.
I’m going to start sewing my suit now.