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[P]
Gecko feet in-hair-ently sticky

By janra in Science
Fri Oct 18, 2002 at 06:11:38 AM EST
Tags: Science (all tags)
Science

Geckos have the ability to run straight up a polished glass wall with no more effort than they use when running straight up a rough tree trunk or upside down on a ceiling, and we finally know why: their feet bond on a molecular level to the surface using van der Waals forces, the weak electrostatic attraction between molecules. This hypothesis was first suggested in the 1960s, when a German researcher discovered that geckos stick better to surfaces with higher surface energy. When the electrons on an overall neutrally charged molecule move at random around the molecule, one end can be briefly more negative and the other more positive. In close proximity to other molecules, these charge fluctuations become synchronized and produce a steady electrostatic attraction between the molecules.


There are hundreds of species of geckos worldwide, varying in size from 1.5-35cm, with this unusual climbing ability. They live in the tropical regions of the world, and are primarily nocturnal. Geckos are also one of the few lizards with a voice, and usually chirp or click.

Past hypotheses, now all disproved, have ranged from microscopic suction cups, adhesive secretions, chemical bonding, capillary adhesion, and tiny hooks. Many of these were simple to disprove: tiny hooks would not work on a molecularly smooth surface such as polished glass, which geckos can climb with ease; suction cups would require a lot of force to break the seal and also wouldn't work in vacuum, while geckos lift their feet as easily as if they weren't sticky at all and their feet still stick under vacuum; and geckos have no glands on their feet to produce any secretions.

The bottom of a gecko foot is covered with tiny hairs called setae, each 100μm long and tipped with about a thousand even smaller hairs with spatula-shaped tips called spatulae, each 200nm around.

These setae are the key to the gecko's climbing ability.

In 2000, researchers took a single seta and attempted to measure its adhesive force using a microscopic, 2-dimensional force sensor. The forces on the setae can be parallel or perpendicular to the surface the gecko is climbing, depending on the orientation of the surface, so a 1-dimensional sensor wouldn't accurately measure the adhesive force.

Simply touching the seta to the sensor got no results; the seta wouldn't stick at all. After observing a gecko on a treadmill, the researchers noted that the gecko placed its palm first, then uncurled its toes to set them down and apply its grip. They then tried to touch the seta to the sensor at the same angle the gecko used when placing its setae on the treadmill's surface, pushing into the surface then pulling back along it the same way the gecko does to increase contact and adhesion. It stuck.

It also adhered with a force of 200μN, 10 times more than they had expected based on studies of adhesive force done on the whole gecko, and right in the middle of the range of van der Waals forces. A single seta adheres with enough force to support an ant; if all setae in a large gecko such as the Tokay gecko, 35cm long and the gecko used in the experiments, were in full use simultaneously, they would adhere with enough force to support an adult human. The stability of the surface they adhere to, however, is another matter entirely.

Also based on their observations of the walking gecko, they found that the gecko curled its toes to lift its feet, in effect peeling the rows of setae off the surface. Applying that observation to the microscopic force sensor, they found that if they increased the angle of a "stuck" seta to approximately 30 degrees, it released easily and without needing to overcome the seta's maximum adhesion, explaining why a gecko can stick incredibly well to any surface, and yet lift its feet easily and quickly enough to run at speeds of up to 1m/s on a vertical polished glass wall.

At this point, the researchers had strong evidence for the van der Waals hypothesis - but still couldn't rule out capillary adhesion.

In August of 2002, after further studies, capillary adhesion was finally disproved. The researchers tested adhesion on hydrophobic and hydrophilic materials, and the seta stuck to both with the same force. They also noted that the seta itself was hydrophobic, making the use of water's surface tension as an adhesive even more unlikely.

They also made two setae of different synthetic materials, silicone rubber and polyester, and tested their adhesion. The material forming the setae did not affect the adhesive force, confirming again that it was van der Waals forces and not chemical bonding or capillary effects, which would be dependant on the chemical composition of the setae and the surface, that provided the adhesion. The materials chosen for the artificial setae were selected because they can be easily molded, an important consideration in potential future use of this technology.

The setae and their spatulate tips provide the most intimate contact possible with a surface short of actual chemical bonding, which is what allows van der Waals forces to come into play. A computer model was created to determine the ideal shape for a tip, assuming van der Waals forces as the adhesive; the final model was nearly identical to the natural setae tips found on gecko feet.

Now that artificial setae tips have been successfully made and proven to stick as effectively as natural ones, the door is open for the development of a "gecko tape" that would have potential applications in nearly every industry, as well as in the home. The manufacture of any quantity of setae is currently beyond our capabilities, but that could change now that we know it will work. And if it doesn't, we can harvest setae from geckos as they shed their skin and setae every few months. It's not mass-production, but it would provide plenty of setae for the micro-applications.

A "gecko tape", like gecko feet, would be strongly adhesive yet easy to remove; would leave no residue; would be self-cleaning and reusable; and would stick to any surface (except teflon, which has such a low surface energy even van der Waals forces don't work on it), no matter how smooth or rough and under any conditions, including under water and in vacuum.

A tape with those properties would be useful in many ways for many reasons. A clean-room environment would appreciate the lack of residue; a micromanufacturer or microsurgeon would appreciate the ability to manipulate tiny objects by attaching a single setae, and easily releasing it when finished; astronauts would appreciate the adhesion in vacuum; robots with sticky feet could be made to negotiate difficult terrain, to help search and rescue teams or scientists exploring unstable or difficult to navigate areas such as collapsed buildings, lava tubes, or underwater caves, or even to explore the lunar or martian surface.

In a move potentially disconcerting to duct tape enthusiasts, 3M is already negotiating to license the patent, so it can manufacture its own "gecko tape."

General references and other sources:

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Related Links
o Scientists unlock secret of gecko glue, 2000
o Scientists prove how geckos stick, 2002
o Dr. Kellar Autumn
o Also by janra


Display: Sort:
Gecko feet in-hair-ently sticky | 133 comments (120 topical, 13 editorial, 1 hidden)
i must say (3.25 / 4) (#3)
by VoxLobster on Fri Oct 18, 2002 at 12:45:51 AM EST

on behalf of people who like puns everywhere -- Damn you!! That's just wrong!

VoxLobster
I was raised by a cup of coffee! -- Homsar

thank you (3.00 / 1) (#4)
by janra on Fri Oct 18, 2002 at 12:47:31 AM EST

but what about the article?


--
Discuss the art and craft of writing
That's the problem with world domination... Nobody is willing to wait for it anymore, work slowly towards it, drink more and enjoy the ride more.
[ Parent ]
don't change it; puns are supposed to be evil! n/t (3.00 / 1) (#10)
by inadeepsleep on Fri Oct 18, 2002 at 01:13:55 AM EST




[ Parent ]
Visited the scientists (4.60 / 10) (#14)
by BloodmoonACK on Fri Oct 18, 2002 at 01:40:26 AM EST

The scientists who did the expirament that seemed to confirm the van der Waals forces hypothesis are located at Lewis and Clark College in Portland, Oregon. About a year ago I was in High School in Portland and I visited a fair showing off recent expiraments. I remember this one particularly because I had just learned about van der Waals forces in Chemistry and thought this looked interesting. They had an example Gecko seta attached to a glass slide. I don't exactly remember how they did it, but I remember pulling something along it to feel how strong it gripped. I was surprised - this incredibly tiny thing gripped HARD. It's similar to how they always say a spider web is stronger than steel per cubic inch? When you finally find one thick enough that it takes a while to give way but is still thing - it's the same kind of weird feeling. Oh well, just giving my experiences with this.

"It's like declaring a 'war on crime' and then claiming every (accused) thief is an 'enemy combatant'." - Hizonner

Very interesting... (4.45 / 11) (#15)
by drachen on Fri Oct 18, 2002 at 01:43:39 AM EST

I wonder if a possible application of these 'setae' could be used in things like tire treads, or in other places where they could be used to enhance traction and not necessarily just be used as an adhesive. Basically, using this "technology" if you will as the gecko itself does: to help in our own transportation. If this works well even on wet surfaces, this could possibly be a nice alternative to rubber tires which have significantly less traction on wet surfaces.

Just a thought. If this can be mass-produced it just might be one of the greatest things since velcro!

(By the way, excellent article!)

Tires (none / 0) (#58)
by Lynx0 on Fri Oct 18, 2002 at 01:45:15 PM EST

While it would be cool to be able to drive up walls with gecko-tires, it's pobably not very energy efficient to have tire with gecko-like setae. While driving the tires would constantly rip single rows of setae off the pavement, which would be like driving with velcro tires...

[ Parent ]
peeling up setae (none / 0) (#60)
by janra on Fri Oct 18, 2002 at 01:50:42 PM EST

Actually, the neatest thing about the setae, was that they were simultaneously extremely sticky and easy to peel off.

In the case of car tires, they'd have to be mounted so that the angle between the setae and the road increased to the release point just as the tire would be leaving the road. Tricky, but it might be doable. The same goes for gecko gloves or shoes.


--
Discuss the art and craft of writing
That's the problem with world domination... Nobody is willing to wait for it anymore, work slowly towards it, drink more and enjoy the ride more.
[ Parent ]
Applications? (4.16 / 6) (#20)
by Talez on Fri Oct 18, 2002 at 03:56:41 AM EST

Maybe Spiderman for real?

Si in Googlis non est, ergo non est
Gecko on a treadmill. (3.40 / 5) (#24)
by tonyenkiducx on Fri Oct 18, 2002 at 06:28:54 AM EST

Id *love* to see that. Hehe.

Tony.
*TIroCllA* *NTrSoEllE* *YTrOolUl*
I get paid in crumpled up fivers, its all the schoolkids can afford these days. There spending all t
sure (4.66 / 6) (#36)
by janra on Fri Oct 18, 2002 at 10:34:52 AM EST

It's right here
--
Discuss the art and craft of writing
That's the problem with world domination... Nobody is willing to wait for it anymore, work slowly towards it, drink more and enjoy the ride more.
[ Parent ]
Thats one of the funniest things Ive EVER seen.. (4.50 / 2) (#44)
by tonyenkiducx on Fri Oct 18, 2002 at 11:42:06 AM EST

Almost as good as this..
Cow Falling Over

Tony.
*TIroCllA* *NTrSoEllE* *YTrOolUl*
I get paid in crumpled up fivers, its all the schoolkids can afford these days. There spending all t
[ Parent ]
But will it... (4.00 / 10) (#25)
by evilpenguin on Fri Oct 18, 2002 at 07:04:02 AM EST

...save me money on car insurance?

Yes, that was horrible.
--
# nohup cat /dev/dsp > /dev/hda & killall -9 getty
Desert Gecko? (1.47 / 17) (#28)
by ChiefHoser on Fri Oct 18, 2002 at 08:26:29 AM EST

1.Geckos have the ability to run straight up a polished glass wall

2.There are hundreds of species of geckos worldwide, varying in size from 1.5-35cm, with this unusual climbing ability. They live in the tropical regions of the world...

I hope you realize that not all gecko's can climb up walls. There are many different species of "desert" geckos. These geckos have a slightly different foot structure based on claws. This causes the ability of climbing walls to not exist in these species of geckos. As to point 2, not all geckos live in the tropics, as said earlier there are many species of desert geckos (of which the leopard gecko is one of the more popular as a pet).

If you are going to talk about geckos it would be nice if you knew some more about them.
-------------

Chief of the Hosers
Oh, get over yourself (4.50 / 8) (#30)
by tuxedo-steve on Fri Oct 18, 2002 at 08:55:41 AM EST

If you are going to talk about geckos it would be nice if you knew some more about them.
I mean, jeez. That was a really interesting article. The fact that certain species do not have this ability is beside the point, worth a footnote at best. The fact that the article poster did not mention it did not detract from the quality of the article.

If you've got something to add to the article, do so, but do it gracefully. Do otherwise at risk of appearing an arrogant, self-important wanker.

Kudos to the article poster. One of the more interesting things I've read on K5 in some time.

- SMJ - (It's not just a name - it's a bad aftertaste.)
[ Parent ]
Agreed! (4.00 / 1) (#37)
by timbley on Fri Oct 18, 2002 at 10:38:48 AM EST

For such an informative article, the author can be forgiven for exaggerating the number of gecko species with this trait.
--
YOU CAN NEVER GO BACK            FREE EARTH!
[ Parent ]
actually (none / 0) (#39)
by janra on Fri Oct 18, 2002 at 10:58:11 AM EST

I said there were hundreds of species of gecko, then in a separate statement said that geckos could stick to things. I probably could have added the word "most" to the second, though.


--
Discuss the art and craft of writing
That's the problem with world domination... Nobody is willing to wait for it anymore, work slowly towards it, drink more and enjoy the ride more.
[ Parent ]
Woohoo! (none / 0) (#51)
by NFW on Fri Oct 18, 2002 at 12:56:42 PM EST

If you've got something to add to the article, do so, but do it gracefully. Do otherwise at risk of appearing an arrogant, self-important wanker.

Amen to that. I was starting to think that I was the only person in the world who saw that kind of crap as... crap.

It's not just you, Hoser.... I have no idea who you are, other than this one post, but every online community seems to be positively infested with e-holes. I'm just pleasantly surprised to find that I'm not the only person who sees it that way.


--
Got birds?


[ Parent ]

Yeah! -- shape up or ship out! (none / 0) (#55)
by neojoat on Fri Oct 18, 2002 at 01:20:50 PM EST

Better yet, somebody get a rope and find a bush.

[ Parent ]
All geckos can stick (4.00 / 1) (#102)
by epepke on Sat Oct 19, 2002 at 05:24:42 AM EST

The only thing is, you have to throw some of them harder.


The truth may be out there, but lies are inside your head.--Terry Pratchett


[ Parent ]
I'm in the wrong industry (4.12 / 8) (#31)
by RavenDuck on Fri Oct 18, 2002 at 09:15:02 AM EST

When I read these articles I constantly think I'm in the wrong line of work. I want to be the scientist whose job it is to try and stick geckos to things.

You get a bunch of geckos, and put them on all sorts of things, turn them in all directions, shake them around and try and get them to fall off (without hurting them, of course). Where can I sight up for a grant to do this sort of thing?

On a slightly more serious note, this would be a much better explanation for Spider-Man's stickyness than the little barbs that come out of his hands, as suggested by the recent movie (I'm not sure if the original comics ever addressed the issue).

I'd sign up for gene therapy to cover my hands and feet with these setae so that I could hang off the ceiling (nothing too high though, I'm not great with heights).

--
For murder, though it have no tongue, will speak
With most miraculous organ.

UHF (none / 0) (#80)
by epepke on Fri Oct 18, 2002 at 05:20:53 PM EST

This puts me in mind of "The turtle is nature's suction cup" sequence from the Weird Al movie UHF. I guess the remake will have to use geckos.

I also wonder, if they do make a gecko tape, if they'll have to license IP rights from Geico Direct.


The truth may be out there, but lies are inside your head.--Terry Pratchett


[ Parent ]
spiderman (5.00 / 1) (#123)
by tgibbs on Sun Oct 20, 2002 at 12:02:20 PM EST

On a slightly more serious note, this would be a much better explanation for Spider-Man's stickyness than the little barbs that come out of his hands, as suggested by the recent movie (I'm not sure if the original comics ever addressed the issue).

Unless, of course, those "barbs" have invisible microscopic hairs on them....

[ Parent ]

Spiderman (5.00 / 1) (#128)
by digitaldust on Wed Oct 23, 2002 at 01:13:53 PM EST

It got explained way back in the 60s, for spidey it was supposed to be atomic force suppresion that made him stick to walls. Which is good ol' fashioned Marvel pseudoscience.

I vaguely remember others like nightcrawler using micromolecular hooks.

[ Parent ]

Hm. (2.00 / 9) (#33)
by ubu on Fri Oct 18, 2002 at 09:44:25 AM EST

Been posted on Slashdot not just once, but twice.

Ubu


--
As good old software hats say - "You are in very safe hands, if you are using CVS !!!"
Yeah... (none / 0) (#53)
by NFW on Fri Oct 18, 2002 at 12:59:28 PM EST

But who bothers with slashdot anymore?


--
Got birds?


[ Parent ]

Hm (none / 0) (#62)
by ubu on Fri Oct 18, 2002 at 02:00:53 PM EST

The first posting was in June 2000. Kuro5hin wasn't even a year old, yet.

Ubu


--
As good old software hats say - "You are in very safe hands, if you are using CVS !!!"
[ Parent ]
So what. (4.00 / 2) (#106)
by Arkayne on Sat Oct 19, 2002 at 09:24:23 AM EST

I don't read Slashdot, so it's new to me. I'm willing to bet I'm not the only one, either. I'm becoming more and more amused by people who seem to make it their hobby to find articles cross-posted on both sites. What are they saying, exactly? "Whoever posts first gains authority to speak on the subject", or are they implying that they believe everyone visits both sites? If one newspaper covers an important world event first, do all the others ignore the story?

[ Parent ]
i agree (none / 0) (#133)
by postindustrialist on Thu Dec 26, 2002 at 01:40:18 AM EST

totally correct.. never used slashdot and never will. just recently joined k5 after lurking for a few months. too many people are negative on sites such as these and get pissed off simply for a difference in opinion or inane shit like this. who the hell cares if it appeared elsewhere first? it's not exaclt plagerism nor is it anything of significant importance. i rather like the article and would not have heard about it any other way
oooh.. looks likes somebody has anger problems.
question everything.
this sig is only one hundred and fifty characters long and it's still not eno
[ Parent ]
Awesome. Now maybe she'll believe me. (3.75 / 4) (#34)
by Iesu II on Fri Oct 18, 2002 at 09:44:50 AM EST

My SO and I actually had a minor tiff the other day when I told her I'd read about geckos sticking to things with Van der Waals forces. She's like, "You made that up. They're just sticky!" and I'm like, "Dude! No! It's good physics!" and she's like, "Bull," usw. 'Swhat I get for bullshitting too much. Anyway, good job. :)

Just be thankful (5.00 / 1) (#57)
by Scratch o matic on Fri Oct 18, 2002 at 01:43:04 PM EST

that you can argue with your SO about Van der Waals forces.

[ Parent ]
and that is why we need environmentalists (3.50 / 4) (#38)
by turmeric on Fri Oct 18, 2002 at 10:53:19 AM EST

because if the geckos had been extinct this would never have been discovered. and who knows how many other thousands of species there are out there with similar secrets.

Extinction (4.00 / 2) (#40)
by ucblockhead on Fri Oct 18, 2002 at 11:13:45 AM EST

The human presence effects different species differently. While, indeed, humanity has driven many species to the brink of extinction and beyond, there are some lucky species that have actually benefited from human presence (often because humanity drove their major competitors out of the area.) These species include coyotes, rats and racoons. The coyote population today is likely an order of magnitude higher today than it was before people migrated to North American tens of thousands of years ago because humanity drove the major competitor to the coyote, the wolf, to the margins.

Anyway, anyone who has spent time in Hawai'i knows the ubiquity of gecko species there. Like the cockroach, humanity has likely not dented their numbers in the slightest.
-----------------------
This is k5. We're all tools - duxup
[ Parent ]

hollow arguments (none / 0) (#41)
by dirtmerchant on Fri Oct 18, 2002 at 11:39:57 AM EST

you completely missed the point of the previous post. although you both seem to be simply engaged in a process of rhetoric exchange, so i guess this will fall on deaf ears anyway...
-- "The universe not only may be queerer than we think, but queerer than we can think" - JBS Haldane
[ Parent ]
it was a side comment, not a rebuttal (nt) (none / 0) (#43)
by ucblockhead on Fri Oct 18, 2002 at 11:41:54 AM EST


-----------------------
This is k5. We're all tools - duxup
[ Parent ]
Actually... (5.00 / 1) (#59)
by Pseudoephedrine on Fri Oct 18, 2002 at 01:46:11 PM EST

You might rephrase that to say "Without the profitable trade in them, Geckos would be extinct." The majority of geckos alive today were bred by herpetoculturists in captivity for the pet/ hobbyist market. Their natural environments (Indonesia and New Caledonia in particular) are in fact under near to constant erosion from logging and the like, but the population of all known species of geckos that are commercially bred is growing quite quickly.

 
"We who have passed through their hands feel suffocated when we think of that legion, which is stripped bare of human ideals" -Alexander Solzhenitsyn
[ Parent ]

and how many speies are in habitat, undomesticated (4.00 / 1) (#91)
by turmeric on Fri Oct 18, 2002 at 09:41:36 PM EST

and undomesticatable, with just as important secrets?

[ Parent ]
So what are you saying? (none / 0) (#105)
by mindstrm on Sat Oct 19, 2002 at 08:41:10 AM EST

Maybe the majority of geckos you see were bred by herpetoculturists...... but if you go anywhere remotely near the equator, you will find geckos all over the place, in the wild.

To say they would be extinct without profitable trade is absurd; there are probably a hundred of the buggers in my back yard alone.

[ Parent ]

The kinds (5.00 / 1) (#117)
by Pseudoephedrine on Sat Oct 19, 2002 at 06:44:18 PM EST

I'd bet that most of those geckos are all one small family of relatives, probably with a lot of inbreeding. It's all very well if you have hundreds of geckos, but if they're all one or two species, that doesn't say anything about the rest of the various gecko species.

As well, they probably aren't the rarer kinds of geckos - the Tokays discussed in the article, for example (not too rare, but certainly not found indigenously in the Americas and not too common in the wild these days). You might have some House geckos (a genus) of one species or another, but these aren't the endangered species we're talking about. House geckos are the rats of the lizard world is all.

The majority of gecko species are found in New Caledonia, Indonesia and throughout SE Asia. Major deforestation was going on on lot of those places last I heard, and the habitat of these species was vanishing. Most gecko species are just barely hanging on (pardon the pun), and will probably go extinct in the wild within our lifetimes. All the House geckos in your backyard won't save the Tokay or the Chinese Cave Gecko or any of several other species in rather precarious positions.
"We who have passed through their hands feel suffocated when we think of that legion, which is stripped bare of human ideals" -Alexander Solzhenitsyn
[ Parent ]

Gecko extinction (none / 0) (#107)
by djmann88 on Sat Oct 19, 2002 at 11:15:46 AM EST

In australia, geckos are common, many different species. And they wont become extinct soon, because they survive in the urban australian environment, it is common to see them in the cities, (and also 60% of australia is wilderness).

[ Parent ]
The rainforest (5.00 / 1) (#118)
by Pseudoephedrine on Sat Oct 19, 2002 at 06:53:14 PM EST

As I recall, most of that wilderness is scrubland and desert - the rainforests where most of the geckos live comprise a very small portion in the north and south. I'm not too familiar with Australian species of geckos, so I can't tell you what their situation is, but if they're doing well, the rest of SE Asia isn't looking so hot.

Also, don't be too sure you're seeing 'many different species'. Geckos are notorious varietal in colour - especially some of the desert species like the Leopard Gecko, where only body shape identifies one lizard as of the same species as another. And that ignores the abilities of certain species to change their colour slightly, which confuses things even further. You might see fifty different lizards all with highly distinctive body markings (one blue, one brown, one red and one green), but they could all simply be different populations of the same species.

Lastly, make sure you aren't confusing them with anoles. Most people think any small colourful lizard that climbs is a gecko, when in reality, very few are. If you're seeing a lot of lizards around, my guess is that they're anoles of some sort. Geckos, with the exception of the Leopard Gecko (which is probably why it's far and away the most common kind of gecko), don't breed incredibly often or have large broods. Anoles do both. I know down in Hilton Head, South Carolina, where I used to go when I was much younger, we often called lizards 'geckos' that I realise in hindsight were actually anole species. The easiest clue is the eyes. Though it's not a hundred percent, usually geckos have "slit" eyes like a cat, while anoles have more or less recognisable eyes with circular pupils. You might do well to check and see if those 'geckos' running around really are geckos.

"We who have passed through their hands feel suffocated when we think of that legion, which is stripped bare of human ideals" -Alexander Solzhenitsyn
[ Parent ]

There are wild Geckos even in Europe... (none / 0) (#130)
by El Tangas on Fri Oct 25, 2002 at 02:48:32 PM EST

There is a mediterranean species in my country, they often enter the houses. We can find them in the roof near light bulbs, catching moths.

[ Parent ]
Why does Teflon stick to the pan? (4.00 / 1) (#42)
by Ricdude on Fri Oct 18, 2002 at 11:41:51 AM EST

...would stick to any surface (except teflon, which has such a low surface energy even van der Waals forces don't work on it)

Slightly off topic, but why does teflon stick to the pan?

I could be wrong (5.00 / 1) (#46)
by KnightStalker on Fri Oct 18, 2002 at 12:09:24 PM EST

but I think it's because the pan surface is not perfectly smooth; it's covered with pits and bumps that the teflon flows around, then hardens. For example, the pan might contain something like this. If the teflon hardens around it, it'll stay.

   ___
___\ /_ __
      / \
      ^^^

Or maybe it's my tendency to take people way too literally biting me in the ass again. :-)

[ Parent ]

you are right (n/t) (none / 0) (#49)
by elias on Fri Oct 18, 2002 at 12:24:30 PM EST



[ Parent ]
Another suggestion? (none / 0) (#54)
by neojoat on Fri Oct 18, 2002 at 01:11:55 PM EST

Maybe the teflon mixture contains a bit of metal and electrostatic plating methods are used?

[ Parent ]
Article about this (5.00 / 1) (#81)
by panner on Fri Oct 18, 2002 at 05:25:51 PM EST

I saw the same question on K5 a while ago, and someone responded with this: Why Teflon Sticks to the Pan. The very basic process is to blast the pan with grit, forming pits to help the molecules cling. However, modern pans apparently go far beyond that. Read the article for the full description.



--
Keith Smiley
Get it right, for God's sake. Pigs can work out how to use a joysti
[ Parent ]
Slightly Old News... (3.00 / 1) (#45)
by DLWormwood on Fri Oct 18, 2002 at 11:44:49 AM EST

...but an otherwise good beginning to the Science section. Keep it up!
--
Those who complain about affect & effect on k5 should be disemvoweled
old, yeah ... 2 months old (none / 0) (#61)
by janra on Fri Oct 18, 2002 at 01:56:18 PM EST

The most recent articles and press releases I was working from are dated August of this year. There is some background information taken from the 2000 information. I wrote the article in September, for the September issue of the engineering student newspaper at UBC.

Then this nice shiny new Science section appeared, and it looked so lonely and empty I thought I'd submit the article I wrote last month :-)


--
Discuss the art and craft of writing
That's the problem with world domination... Nobody is willing to wait for it anymore, work slowly towards it, drink more and enjoy the ride more.
[ Parent ]
It's sticks mechanically instead of chemically (5.00 / 2) (#47)
by zimslur on Fri Oct 18, 2002 at 12:14:22 PM EST

From http://users.efni.com/~paradox/teflon/uses.html "Today pot makers sandblast the inside of the pan to make it rough, then apply a primer. Teflon is embedded in the primer and is mechanically, not chemically, held on to the surface of the frying pan. Du Pont has invented a new primer to apply Teflon on a smooth surface, but aren't explaining how it works." :)

Oh no! =:-o (none / 0) (#126)
by ucblockhead on Sun Oct 20, 2002 at 10:31:22 PM EST

They are using crushed gecko feet!! The bastards!!!
-----------------------
This is k5. We're all tools - duxup
[ Parent ]
Would it be possible... (4.00 / 2) (#48)
by Stick on Fri Oct 18, 2002 at 12:19:11 PM EST

To turn yourself into spiderman using this knowledge?


---
Stick, thine posts bring light to mine eyes, tingles to my loins. Yea, each moment I sit, my monitor before me, waiting, yearning, needing your prose to make the moment complete. - Joh3n
Gecko-Man, only. (5.00 / 2) (#89)
by porp on Fri Oct 18, 2002 at 08:28:04 PM EST

Unfortunately, clever application of van der Waals forces will not give you superhuman strength, a 'spider sense', or the ability to formulate super-strong synthetic spider silk, much less the ability to shoot it out of a wrist mounted gadget. Most devastatingly, it will definitely not attract hot redheaded girls to you.

[ Parent ]
No, but... (5.00 / 2) (#94)
by kerinsky on Sat Oct 19, 2002 at 01:59:46 AM EST

No, but it could attach hot redheaded girls to you...

That's the Next best thing right?

-=-
Aconclusionissimplytheplacewhereyougottiredofthinking.
[ Parent ]

Yes, but... (5.00 / 1) (#125)
by porp on Sun Oct 20, 2002 at 04:36:45 PM EST

Attachment isn't bad, but it doesn't leave any room for that grinding motion that we all feel an urge to do when we see a redheaded Kirsten Dunst. It'd be like trying to have sex with your own underwear, while it's on. Now something's tingling, and it's not my setae...

[ Parent ]
Correction regarding van der Wal (3.80 / 5) (#52)
by egg troll on Fri Oct 18, 2002 at 12:57:43 PM EST

van der Wal is not a physicist. It may suprise you to know that he's really a right fielder for the New York Yankees.

He's a bondage fan, a gastronome, a sensualist
Unparalleled for sinister lasciviousness.

a bit o/t (4.00 / 1) (#63)
by phuzz on Fri Oct 18, 2002 at 02:12:10 PM EST

I was just wondering, geckos are cool, so I want one or two running round on the roof. Anyone know how difficult they are to keep? (bearing in mind I used to keep snakes).  Plus wouldn't the best use of 'gecko tape' be to put it on your shoes so you could run up walls, (to, say, recapture one of your geckos that got out of it's cage?).

Btw, thats a BAD pun, nice article tho.

easy, I think (none / 0) (#78)
by sully on Fri Oct 18, 2002 at 05:14:45 PM EST

I had one when I was a kid. I thought it was extremely easy. But then it died inexplicably, so maybe I was missing something important....


-------------
The opinions expressed above are not necessarily those of my prefrontal cortex.
[ Parent ]
uncle raises them (5.00 / 1) (#97)
by Phantros on Sat Oct 19, 2002 at 03:22:02 AM EST

My uncle raises and breeds them (as a hobby).

Requirements: A terrarium, reasonably constant temperature, and food that you can get at most decent pet stores. In other words, easy.

4Literature - 2,000 books online and Scoop to discuss them with
[ Parent ]

I have tons of them... (5.00 / 1) (#104)
by mindstrm on Sat Oct 19, 2002 at 08:36:44 AM EST

living outside my house of course.  I suppose it helps that I live in the tropics.

I have to say, though, since I found the outside of the house swarming with the little creatures, I haven't seen a single cockroach since I moved in.

The gecko tape would work, perhaps, but would the wall have the structural integrity to support your weight?

[ Parent ]

People keep forgetting that... (none / 0) (#131)
by DavidTC on Sun Oct 27, 2002 at 12:23:56 AM EST

Here's a thought experiment: can you stick four bolts into random places in a wall and hang onto them? Of course you can't on a sheetrock wall, that's a good way to rip the wall apart and end up on your ass.

For that matter, even if you had a wall strong enough, is the surface strong enough, or would you just rip the top layer of paint/wallpaper/paper on sheetrock/etc off?

If you had perfect glue, could you glue 200 pounds to the ~16 square inches your hands and feet cover?

-David T. C.
Yes, my email address is real.
[ Parent ]

van der Waals forces (2.33 / 6) (#64)
by the on Fri Oct 18, 2002 at 02:31:43 PM EST

These forces exist between all molecules. So why does this force allow Geckos' feet to stick to walls but my feet don't. They're both made of molecules. van der Waals forces are just electrostatic forces between dipoles are they not? Why don't the same dipoles form on my feet?

--
The Definite Article
the key is the hairs (5.00 / 2) (#65)
by janra on Fri Oct 18, 2002 at 02:39:07 PM EST

The setae tips get in such intimate contact with the surface the gecko is walking on it makes pressing your hand against glass look like two mountain ranges pressing together.

There are van der Waals forces in effect between our hands and feet and a surface, but because on an atomic scale there's only a tiny amount of the surface that actually touches, it doesn't make much difference.


--
Discuss the art and craft of writing
That's the problem with world domination... Nobody is willing to wait for it anymore, work slowly towards it, drink more and enjoy the ride more.
[ Parent ]
So any two surfaces might bind through vdW forces? (3.00 / 1) (#67)
by the on Fri Oct 18, 2002 at 03:07:28 PM EST

So if I took a piece of metal and a piece of rock and polished a surface of each to the point where they were flat to within one or two molecules they'd stick when brought into contact?

--
The Definite Article
[ Parent ]
yes (none / 0) (#69)
by janra on Fri Oct 18, 2002 at 03:12:53 PM EST

You'd have to get them completely smooth on a molecular level, but yes. For a lot of solids and liquids, van der Waals forces are all that holds them together.


--
Discuss the art and craft of writing
That's the problem with world domination... Nobody is willing to wait for it anymore, work slowly towards it, drink more and enjoy the ride more.
[ Parent ]
Define "bind" (none / 0) (#72)
by nusuth on Fri Oct 18, 2002 at 03:23:13 PM EST

A lot of "friction" is actually bond formation and breakage across surfaces. Vast majority of these bonds are of Van der Walls type.

[ Parent ]
Machined metal (none / 0) (#74)
by wurp on Fri Oct 18, 2002 at 03:44:29 PM EST

does this pretty often, I understand.  If the surfaces are too finely machined, and you leave one lying flat on top of the other for any length of time, they have a tendency to stick together permanently.
---
Buy my stuff
[ Parent ]
Cool (none / 0) (#90)
by the on Fri Oct 18, 2002 at 08:52:51 PM EST

I want to do this!

--
The Definite Article
[ Parent ]
I don't think that is Van der Waals force (none / 0) (#109)
by roystgnr on Sat Oct 19, 2002 at 01:23:41 PM EST

I don't remember the exact mechanism (Atomic diffusion? Metallic bonding?), but the strength of the effect depends on the particular metals you stick next to each other.  Putting brass in perfect contact with aluminum shouldn't fuse them, for example, but putting polished surfaces of brass in contact with brass or aluminum in contact with aluminum can.

[ Parent ]
Easy experiment (5.00 / 2) (#124)
by EggplantMan on Sun Oct 20, 2002 at 01:15:01 PM EST

Place two flat sheets of glass on top of each other and tell me how hard it is to separate them.

[ Parent ]
Did you read the article? (5.00 / 1) (#103)
by mindstrm on Sat Oct 19, 2002 at 08:33:58 AM EST

Man,  this is starting to sound like slashdot.

Your feet do not make intimate enough contact to the wall you are trying to climb. A gecko's foot has a bazillion microscopic hairlike things that provide an extreme level of contact with whatever surface they are on.

[ Parent ]

intimate? (none / 0) (#132)
by postindustrialist on Thu Dec 26, 2002 at 01:08:46 AM EST

now just how intimate do we have to be? "hey baby, what's your sign you sexxxxxxy wall you" *wink wink*
oooh.. looks likes somebody has anger problems.
question everything.
this sig is only one hundred and fifty characters long and it's still not eno
[ Parent ]
Interesting support for evolution (3.00 / 2) (#66)
by Edgy Loner on Fri Oct 18, 2002 at 02:54:07 PM EST

The gecko setae are a rather complex and unique structure that solves a common problem, namely climbing. Other climbing critters make do with adapted claws, prehensile digits or some combination of the two. Apparently the gecko line had some fluke mutation at some point in their history that gave them structures on their feet that could become setae.Only decendants from this line were in a position to have setae.

The end result is that geckos, and only geckos have this keen climbing tool. Setae are sufficiently complex and 'non-standard' that the probablity of developing them is low and hence restricted to this one group of lizards. Contrast this to what things would look like in an intellegently designed biosphere: setae would either be common, as they are so useful, or nonexistent as claws are 'standard equipment' and work perfectly well.

Once again the observed universe conforms more closely to the unguided forces of nature, than to the controlled tinkerings of a ominipotent master craftsman.



This is not my beautiful house.
This is not my beautiful knife.
nope, geckos aren't the only ones (5.00 / 2) (#68)
by janra on Fri Oct 18, 2002 at 03:11:08 PM EST

There are a few other critters that have seta-like structures on their feet. A couple of lizards, and some insects. They're not exactly the same, but they work in much the same way; the gecko is sort of the "deluxe model" (to quote Dr. Autumn) with the most setae per foot, and the most spatulae per setae.
--
Discuss the art and craft of writing
That's the problem with world domination... Nobody is willing to wait for it anymore, work slowly towards it, drink more and enjoy the ride more.
[ Parent ]

Interesting (none / 0) (#71)
by Edgy Loner on Fri Oct 18, 2002 at 03:22:45 PM EST

It does sound like setae are fairly rare though, so I think my point is still valid. Do they appear to be indepently developed or adapted from a common ancestor.

This is not my beautiful house.
This is not my beautiful knife.
[ Parent ]
Don't know for sure (5.00 / 1) (#73)
by janra on Fri Oct 18, 2002 at 03:31:38 PM EST

But I'd bet they evolved independently. I mean, you'd have to go pretty far back to find a common ancestor to both lizards and insects.


--
Discuss the art and craft of writing
That's the problem with world domination... Nobody is willing to wait for it anymore, work slowly towards it, drink more and enjoy the ride more.
[ Parent ]
So I guess the fact that every room in my house... (3.66 / 3) (#70)
by the on Fri Oct 18, 2002 at 03:21:00 PM EST

...has door handles, lamps, tables, chairs etc. made by different manufacturers and using different technologies goes to show that it wasn't thought out by an intelligent agent.

--
The Definite Article
[ Parent ]
Not quite (4.33 / 3) (#75)
by Edgy Loner on Fri Oct 18, 2002 at 03:47:01 PM EST

What you see in designed systems are things that are, well, designed. They match their function extremely well, and don't neccesarily derive from semething else. In evolved systems you may not be able to get there from here. Bats would work a lot better if they had an extra set of limbs, and not have to recycle their forelimbs for wings. Unfortunately, vertabrates only have 4 limbs, the evolutionary steps to create a new set are too complex to be practical so bats are stuck. So the designed things you see are designed to work specifically to their function, evolved things are made to work - essentially jury rigged.

This is not my beautiful house.
This is not my beautiful knife.
[ Parent ]
evolution: if every room... (4.50 / 2) (#122)
by tgibbs on Sun Oct 20, 2002 at 11:59:02 AM EST

has door handles, lamps, tables, chairs etc. made by different manufacturers and using different technologies goes to show that it wasn't thought out by an intelligent agent.

Certainly not a single intelligent agent. But those differences are small compared to the differences in biological "technologies." It's more like the lights in your kitchen were incandescent bulbs running on DC 12V, those in the bedroom were flourescent bulbs running on AC 110V, those in the living room LEDs running on AC 220V, and those in the bathroom were kerosene lanterns.

[ Parent ]

This is extremely old news (none / 0) (#88)
by fluffy grue on Fri Oct 18, 2002 at 07:26:03 PM EST

According to my mom (a microbiologist), this has been known since the 70s when electron microscopes were all the rage. Bored researchers would put everything they could into electron microscopes. It just wasn't paper-worthy back then.
--
"Is a sentence fragment" is a sentence fragment.
"Is not a quine" is not a quine.

[ Hug Your Trikuare ]

the 70s (4.00 / 1) (#92)
by janra on Fri Oct 18, 2002 at 11:23:10 PM EST

From my reading, I understood that the van der Waals was first proposed as a theory around that time, and was a strong contender, but the last alternate theory was only just finally disproved and van der Waals was proved recently.


--
Discuss the art and craft of writing
That's the problem with world domination... Nobody is willing to wait for it anymore, work slowly towards it, drink more and enjoy the ride more.
[ Parent ]
debris (5.00 / 3) (#98)
by Phantros on Sat Oct 19, 2002 at 03:25:11 AM EST

I'd like to know why microscopic debris doesn't collect on the setae. Does it collect but then is subsequently brushed off when the setae are bent at the proper angle while the gecko walks, or...?

4Literature - 2,000 books online and Scoop to discuss them with

they don't know (4.50 / 2) (#111)
by janra on Sat Oct 19, 2002 at 02:38:24 PM EST

That was one of my questions to Dr. Autumn, and he said it's his next project.

He's stuffed the setae with dirt, small particles, microspheres, all kinds of stuff - and after five or six steps, the gecko's feet were clean again. They don't know why or how, but simply walking cleans it out.


--
Discuss the art and craft of writing
That's the problem with world domination... Nobody is willing to wait for it anymore, work slowly towards it, drink more and enjoy the ride more.
[ Parent ]
I am dumb (none / 0) (#99)
by bugmaster on Sat Oct 19, 2002 at 04:04:14 AM EST

Sorry, my chemistry days are behind me...

How does the gecko get his feet to unstick from the surface when the time comes to lift the foot ? There is no way to turn off the Van der Waals forces, right ? Also, assuming he just tears off one seta at a time, wouldn't the tiny hairs be ripped from the foot ? How quickly do they regenerate ?
>|<*:=

not dumb (none / 0) (#110)
by janra on Sat Oct 19, 2002 at 02:35:27 PM EST

That was covered in one sentence out of the whole article:

they found that if they increased the angle of a "stuck" seta to approximately 30 degrees, it released easily and without needing to overcome the seta's maximum adhesion, explaining why a gecko can stick incredibly well to any surface, and yet lift its feet easily and quickly


--
Discuss the art and craft of writing
That's the problem with world domination... Nobody is willing to wait for it anymore, work slowly towards it, drink more and enjoy the ride more.
[ Parent ]
Still confused (none / 0) (#113)
by bugmaster on Sat Oct 19, 2002 at 04:41:20 PM EST

Yes, I read that sentence actually, I just don't understand it. Why does the seta detach at 30 degrees ?
>|<*:=
[ Parent ]
peeling (3.33 / 3) (#115)
by janra on Sat Oct 19, 2002 at 06:21:16 PM EST

One of the explanations I read (but can't find again, sorry) is that as the angle increases, the thousand spatulae on the seta tip are peeled farther away from the surface - kind of like peeling up tape. It's really hard if you pull on the whole thing at once, but if you start at one end and roll it upward, it comes off easily.

So as the angle increases, fewer spatulae are stuck as the ones at the edge are lifted a few at a time, and at a certain angle enough spatulae have come unstuck that the whole seta pops off. The exact angle, measured at 30 degrees, is most likely due to the arrangement and angle of the spatulae on the seta.


--
Discuss the art and craft of writing
That's the problem with world domination... Nobody is willing to wait for it anymore, work slowly towards it, drink more and enjoy the ride more.
[ Parent ]
just a question (none / 0) (#114)
by Niha on Sat Oct 19, 2002 at 05:41:56 PM EST

It is a quite interesting article. I have just one doubt. You say that geckos live on tropical regions.In that case, what does it come every night to my window? It looks quite like a gecko,and also is quite sticky...(I´ve called it Chris, as I don´t know its gender)

not sure (none / 0) (#116)
by janra on Sat Oct 19, 2002 at 06:23:11 PM EST

It's possible that somebody has been breeding geckos in your area. They're native to the tropics, but can be found outside that area, usually if somebody brings them.


--
Discuss the art and craft of writing
That's the problem with world domination... Nobody is willing to wait for it anymore, work slowly towards it, drink more and enjoy the ride more.
[ Parent ]
I wonder... (none / 0) (#119)
by Andy P on Sat Oct 19, 2002 at 10:05:05 PM EST

I'll make a fortune by patenting Gecko shoes.  I wonder if you need a working model, or just the idea to file a patent request?  I'd make millions selling them to every office building window cleaner, bored rich kid, wannabe rock climber and paparazzi photographer.

Barrels are just crates with delusions of grandeur
I masturbate to AOL commercials

Great topic, good article (none / 0) (#127)
by gr00vey on Mon Oct 21, 2002 at 02:42:55 PM EST

velly velly interesting.....! Thanks for sharing!

Useful concept, bring in the engineers! (none / 0) (#129)
by hatshepsut on Thu Oct 24, 2002 at 01:37:35 PM EST

  • safety equipment (tires, safety gloves, boots, shin pads etc.)
  • tape or strips for use on just about anything (pictures on your walls, anything on slippery surfaces)
  • just about anything in the ISS or space shuttles
  • replace David Letterman's Suit of Velcro (or am I just showing my age?)
Wonder how much we'll have to fork out for the stuff once it becomes available?

Gecko feet in-hair-ently sticky | 133 comments (120 topical, 13 editorial, 1 hidden)
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