A View from David Zax
Superhydrophobicity, Robot Bugs, and You
Jesus of Nazareth can hardly have foreseen the espionage applications of walking on water.
Behold the water strider.
Now, this isn’t an entomology blog, but technology is often at its best when it imitates the feats of the world of insects. Just as the water strider is able to skate along the water, so can a new microbot described in ACS Applied Materials & Interfaces. In fact, the bot, built by a team from the Harbin Institute of Technology in China, goes further–not only can it walk on a water, like a certain foundational figure of a major Western religion, it can jump on water.
The team built upon a water-skimming bot they had published on about a year ago, further setting themselves the challenge of making a robot that could jump on the water without sinking. The downward force of jumping would typically puncture the surface of the water–particularly in a robot like this one, weighting 1,100 times that of an average water strider insect.
So how did the team pull off this miraculous feat? They built five legs for their creature–three stabilizing, two jumping. And they used a very particular kind of material: a “porous, super water-repellant nickel foam.” (The scientific word for such excessive water-repellence, by the way, is “superhydrophobicity.”) A driving system included a miniature direct-current motor plust a reduction gear unit.
The acrobatic robo-bug could jump 5.5 inches vertically and 14 inches horizonatally, or about two times its length, all at a speed of 3.6 mph. “The present finding not only offers a possibility for vividly imitating and better understanding the amazing water-jumping capability of aquatic insects,” say the researchers, “but also extends the application of porous and superhydrophobic materials to advanced robotic systems.”
What are the applications of such a device? The researchers claim such robots could monitor water quality (and, for that matter, if you think about it, the quality of the air up to 5.5 inches above the water). They add that the robots might someday “act as tiny spies”–because let’s face it, when you’re a head of state relaxing on a lake in August, that leaping robotic insect is the last thing you’re expecting to spy on you.
OK, researchers–I’ll buy that. Whatever helps you guys get your grants from military and environmental agencies. And in the end, isn’t coolness the greatest application of all?