A few weeks ago, as he was nestled in bed with with two copies of Tolstoy’s The Death of Ivan Ilyich (one in each hand — helps reduce time wasted flipping pages), Pax Arcana bolted out of bed, flipped on the lights, and stared menacingly at the headboard — fists clenched, battle stations manned.
Such dramatic action was necessary after seeing what can best be described as a “blond tarantula” dangling from its silky thread not 6 inches above my face. The spider itself was at least five inches across and wiggling furiously, but somehow managed to disappear completely after I bounded to the ready.
The dreamy and precise Mrs. Pax Arcana contests that I had merely fallen asleep and was having a peculiarly realistic dream about a big-ass blond tarantula threatening to deface my face. But I know better. That thing was real, people.
But maybe it wasn’t a spider at all.
Just a few miles from Pax Domicilus, scientists at MIT are busy developing enough nightmare fuel to keep me awake for the next decade. Their latest triumph is to create an adhesive made of carbon nanotubes that mimics gecko feet:
“People have tried to mimic the gecko structures, but it’s not easy,” says Dai. Using a silicon substrate, he and his group grew arrays of vertically aligned carbon nanotubes topped with an unaligned layer of nanotubes, like rows of trees with branching tops. The adhesive force of these nanotube arrays is about 100 newtons per square centimeter–enough for a four-by-four-millimeter square of the material to hold up a 1,480-gram textbook. And its adhesive properties were the same when tested on very different surfaces, including glass plates, polymer films, and rough sandpaper.
I know what you’re saying. “Hey neato,” you’re saying. “This breakthrough will lead to longer lasting duct tape that’s easier to peel off!”
Well you’re exactly right. Only substitute long-lasting e-z peel duct tape with scary ass wall-scaling self-cleaning space robots:
Wall-climbing robots will require adhesives that work again and again without wearing out or getting clogged with dirt. “We want a robot to take more than 50 steps in a dirty environment,” says Dhinojwala. No one has demonstrated strong gecko-inspired adhesives that can do this. And nanotube adhesives will need to be grown on different substrates than those used so far. Carbon nanotubes are easy to grow on silicon wafers; creating large areas of the adhesive wouldn’t be a problem. But “we’re not going to stick silicon wafers to robot feet,” says Dhinojwala.
Dai says that carbon nanotubes’ versatility may help overcome the dirt problem. These structures can readily be functionalized with proteins and other polymers. Dai is developing adhesive nanotube arrays coated with proteins that change their shape in response to temperature changes. A robot could have feet that heat up when they get clogged, shedding dirt so that it can keep walking.
Congratulations, science nerds! Your wall-climbing, shapeshifting, hot footed lizard bots are on their way! Now if you’ll excuse me I have some windows to nail shut.
Sticky Nanotape [Tech Review]