“You see, a few years ago some fellows at Berkeley and at Carnegie Mellon had the idea that being able to emulate a gecko and walk up walls and across ceilings might, and I’m sure you’d agree, be a fun and useful thing.” Forrester stopped long enough to grin from ear to ear at Gries. “Think about it. If we could create a material that enabled us to have the nimble little lizard’s incredible grip, wow, the applications would be endless.
“The efforts of those fellows made the idea a step closer to reality because they were clever and worked out how to make a material coated with synthetic gecko hairs. Uh, I’m getting ahead of myself. Let me see…” Dr. Forrester ran his fingers through his unruly hair.
“Ah yes, the hairs on gecko feet. Biologists call them ‘setae.’ These little setae are the key to its remarkable grip on just about any surface, rough or smooth, wet or dry, and the things are so sticky that the little lizards can hang from a ceiling with their entire weight held up by a single toe. Isn’t that just marvelous?”
“Yes, I’ve seen little geckos do that trick before. The ones they call leopard geckos are all over Iraq,” Shane added.
“Iraq, yes indeed, leopard geckos, hmm, marvelous.” Forrester chuckled and his belly jiggled like Santa Claus’s. “Well, it wasn’t until as recently as last year that we understood how these little guys can do such a nifty thing. In fact, there was some very, shall I dare say, heated, debate about why geckos’ setae were so fantastically sticky.”
“Really,” Shane asked, trying not to let his eyes glaze over or to check his watch.
“Oh, indeed. There was one school of thought that there was some gluey chemical interaction taking place between their feet and the surface they walked on. But that didn’t pan out. This really clever fellow, uh, named Ron Fearing, and a few of his colleagues at the University of California at Berkeley finally figured it out. Can you believe that it turns out to be an electromagnetic interaction between a gecko’s feet and the surface molecules, wow!” Forrester said excitedly.
“Oh, yes, believe it or not, the adhesion is in fact due to very weak intermolecular attractive forces called van der Waals forces. Amazing, isn’t it?” He chuckled again and spent the next few minutes drawing a diagram of the gecko setae and explaining the van der Waals attraction.
While Forrester’s back was turned, Shane stifled a yawn and did check his watch. He had no more than an hour he could spend here and it was airport food for sure. If he didn’t make it through security, fast, it would be soggy sandwich time.
“The way it works is that the gecko setae measure tens of microns across and at their tiny ends they split into lots of even more tiny, thinner, extremely flexible hairs, each just hundreds of nanometers in diameter; now, isn’t Mother Nature just incredible?” the scientist added, looking over his shoulder at his audience and apparently failing to notice that Shane’s eyes were creeping closed.
“These little hairs then broaden out into flat spatulas, just like egg turners, at their tips. The wonderful little buggers can bend and conform to the surface of the wall at the molecular level and believe it or not again, this maximizes the surface area contact between the spatula and the surface, which in turn maximizes the van der Waals attractive force. I just can’t hardly believe it, can you?” Forrester seemed almost giddy.
“Uh, no?” Shane added uncertain if the question had been rhetorical or not. He restrained the desire to check his watch again. The guy wouldn’t be hurried by it, he was sure.
“Finally, these other fellows I’ve been talking about figured out how to synthesize the gecko skin. Wonderful ingenuity, wonderful,” Dr. Forrester said enthusiastically. “Modern vacuum deposition, lithography technology, and some other materials technology allowed them to build synthetic gecko setae made from a material called Kapton that you see there in those orange rolls behind you. They made little gecko hairs that measure about two microns in height and about a tenth that in diameter. That is about the same dimensions as gecko hairs are. They made tape that was covered with this gecko hair with a mold created by a lithographic process. And the most wonderful part is that a piece of tape one centimeter square holds around a hunderd million of these little artificial gecko setae and can actually support a weight of one kilogram. Wow! That suggests that a pair of gloves made of this stuff is all it would take to support the weight of a human being!”
“What’s the catch? That sounds too good to be true.” Shane leaned forward at that statement. Second-floor entry wasn’t required that often, but various forms of climbing did occur in infantry combat. A pair of lightweight “super climber” gloves would be a great addition to the infantryman’s pack. Well, it would add a smidgeon of weight, but… no, they could get rid of most ropes, which would drop weight. Weight had been a bugaboo in the infantry field all the way back to the days of Sargon.
“Ah, very astute, very astute, Major,” Forrester replied and frowned. “The previous researchers have never been able to produce a synthetic gecko skin that worked more than a few times. The little gecko hairs get crushed or dirty or something and the material stops sticking to things. Very astute.”
“So, it only works a few times, then you fall off the wall. Hmm, that could be hazardous for Geckoman the superhero, I would think.” Gries smiled and was somewhat disappointed. Even if they could draw it out, they probably wouldn’t be good for more than one use. Start talking about disposable gloves and it would be a pain.
“Oh, yes, Geckoman, funny.” Forrester chuckled like Santa Claus again. “But you see, we’ve figured it out! I think we can deliver a material that will be completely reusable and work for tens of thousands of uses, maybe even indefinitely if it’s cleaned after every few hundred uses. Here, watch this.” Dr. Forrester rummaged through some equipment on one of the cluttered work benches and found what looked like a typical toy’s remote control box.
Forrester flipped some switches and Shane nearly jumped out of his seat as a bright blue toy monster truck slammed into his stool. Forrester continued to flip the control levers on the box, then seemed to get control of how to steer the little monster truck. Shane noticed that the wheels of the truck were “oversized” to say the least. In fact, the wheels were so large that they stuck out in front of and above the little vehicle’s frame. The little toy truck must have been modified with a more powerful motor just to turn those big things over.
“Watch, watch!” Dr. Forrester said as he drove the little monster truck across the room and right up the wall.
“Holy shit!” Gries grinned. “Can I play with that?”
“Sure, go over and pull it off the wall, Major.” Dr. Forrester replied.
Shane crossed the cluttered room, being careful not to trip on some piece of equipment and break it or his neck, then grasped the toy truck. Shane pulled at the truck and it failed to unstick itself from the wall. He got a better grip on the truck and pulled harder — the truck stuck steadfast. He wasn’t sure he could get it off if he planted his feet.
“I love that bit!” Forrester gave a deep belly laugh. “I’m sorry, Major Gries. I couldn’t resist. You see, we figured out that the gecko is clever indeed. He has to twist his foot in a certain motion to release himself — we think. So, you have to do the same with the synthetic material. That’s why I drove the truck up the concrete wall instead of the drywall — I take it you noticed all the spackle in the building.”
“Yes, I did.”
“Well, let’s just say we’ve had a lot of fun with that trick, ha ha.” He laughed again. “You know, it took us forever to develop a tire that would spin with just the right motion that would stick when you want it to and not stick when you want it to. Roll the truck forward and pull up and forward at the same time.”