Scientists discover fractal pattern in Scotch tape

Dec 09, 2010 By Lisa Zyga feature
Peeling at low velocity results in a rough surface, while peeling at high velocity results in a smoother surface. Scientists found that both surfaces exhibit unexpected fractal scaling properties. Image credit: B. N. J Persson, et al.

(PhysOrg.com) -- Clear cellophane tape – which can be found in almost every home in the industrialized world – may seem quite ordinary, but recent research has shown otherwise. In 2008, scientists discovered that, when peeled, Scotch tape produces X-rays that are strong enough to image the bones in a human finger. In a new study, scientists have further investigated what happens when clear tape is peeled, and found that the tape's surface roughness displays a fractal pattern. The findings may lead to a better understanding of the processes involved in peeling, the origin of the X-ray emission, and in the design of better tape that can be reused repeatedly.

The study’s authors, Bo Persson from FZ-Julich in Julich, Germany (who was also a coauthor of the X-ray study), Alexander Kovalev and Stanislav Gorb from the University of Kiel in Kiel, Germany, and Matthias Wasem and Enrico Gnecco from the University of Basel in Basel, Switzerland, have published their results in a recent issue of .

In their study, the scientists used a white-light interferometer as well as an atomic force microscope to look at the tape’s sticky surface after it had been peeled off a hard substrate. They found that slowly peeling the tape leaves behind a rough, white surface on the soft rubber adhesive layer (the white color is due to the large light scattering from the rough surface). On the other hand, peeling the tape more quickly leaves behind a smoother, transparent surface (transparent because there is less light scattering from the smoother surface).

In addition, the scientists were surprised to find that both the rough and smooth surfaces exhibited fractal scaling properties over a wide range of length scales, with a fractal dimension that is typical for surfaces produced by crack propagation. The scientists did not expect this result because of the influence of the surface free energy. That is, elastically soft solids such as the tacky rubber adhesive should deform at short length scales in order to reduce the surface free energy. This should result in a much smoother surface at short length scales (or high magnification) than would otherwise be expected. This effect had already been observed in a different context, but could not be detected on the rubber film of the peeled tape.

These images show the surface profiles of the adhesive side of peeled tape, obtained with the use of a white-light interferometer. A-D show a smooth surface due to fast peeling, while E-H show a rough surface due to slow peeling. A, B, E, and F are at low magnification, while C, D, G, and H are at high magnification. Image credit: B. N. J. Persson, et al.

The findings could help scientists better understand the cause of the X-rays generated from peeled tape, which is thought to be associated with the surface roughness of the tape. Information about the tape’s surface roughness could also be used to explain the maximum emitted photon energy of the tape.

The scientists also suggested that, by understanding the tape’s roughness after peeling, manufacturers could build in a specific roughness during the production process that could stabilize the adhesion, resulting in tape that can be used multiple times without losing its adhesive properties.

Explore further: 'Pixel' engineered electronics have growth potential

More information: B. N. J. Persson, et al. “Surface roughness of peeled adhesive tape: A mystery?” Europhysics Letters, 92 (2010) 46001. DOI: 1209/0295-5075/92/46001

4.6 /5 (29 votes)

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Sciencebee
2.8 / 5 (4) Dec 09, 2010
[quote]In 2008, scientists discovered that, when peeled, Scotch tape produces X-rays that are strong enough to image the bones in a human finger.[/quote]

I'm fairly certain this was not 'discovered' in 2008. I believe some Russian scientists discovered in long ago. Searching now.
Sciencebee
3.9 / 5 (7) Dec 09, 2010
[quote]Russian scientists reported as far back as 1953 that from tape they had detected electrons energetic enough to emit X-rays. “But as far as I can tell, no one ever believed them,” Dr. Putterman said.[/quote]

Sources:
http://www.nytime...ray.html

So I guess the Russians reported the phenomena but it wasn't exactly published research.
NotAsleep
2.3 / 5 (6) Dec 09, 2010
Enough X-ray radiation to image a finger... so are people that frequently use cellophane tape at a higher risk for cancer over their lifetime? I did a quick Google search and could only find the statistic that x-raying a hand is equivalent to a few days of natural background radiation.

Although not directly related to this article, I'd love to see some actual numbers on that. This might finally be the tipping point that pushes me to use metal boxes instead of cardboard and use a welder instead of cellophane
shavera
4.6 / 5 (10) Dec 09, 2010
@NotAsleep: you need to peel the tape in a vacuum. The key is that the electrons escaping the surface of the tape need to decelerate in the peeled off layer, not in collisions with the air between.
Ricochet
5 / 5 (6) Dec 09, 2010
This might finally be the tipping point that pushes me to use metal boxes instead of cardboard and use a welder instead of cellophane


That's a good idea, since welding fumes aren't harmful at all...
Florin_Andrei
5 / 5 (1) Dec 09, 2010
Similar fractal pattern occurs with water / silicon carbide / glass slurry in between two discs of glass, when grinding a telescope mirror, and you lift the upper disc at the end of a grinding session:

http://i.imgur.com/3Pj5w.jpg

Email sent to Bo Persson.

P.S.: This is how grinding is done. Lifting the disc occurs at the end, around 3:43 time:

http://www.youtub...M7A9yTWw
Raveon
1 / 5 (1) Dec 09, 2010
I wonder if shipping department people are getting a significant extra radiation dose, they go through a lot of that tape.
NotAsleep
5 / 5 (3) Dec 09, 2010
@ Ricochet, welding fumes aren't a problem for me. I just use my left lung (my "welding lung") to breath, much in the way that I only use my left eye (my "welding eye") instead of a face shield.

I can't exactly control how my body absorbs x-ray's, though, can I??? You're just not thinking outside the box.

@ Shavera, thanks!
Bobathon
4 / 5 (6) Dec 09, 2010
Scotch tape is also a potent source of antiprotons for particle accelerators, and can be used to cure cancer and grow crops in the desert and cure AIDS.

Thinking outside the box is easy when you're working with loads of scotch tape. It's opening the bloody box that's the problem
Eric_B
1 / 5 (1) Dec 09, 2010
geez...just go back to using rabbit skin glue!
gwrede
3.9 / 5 (7) Dec 09, 2010
To NotAsleep: if tape would generate x-rays without being in a vacuum, then they wouldn't have used the vacuum chamber in the video.

To Sicencebee: commendable effort finding the Russian quote and posting it here!

Another reason why nobody believed the Russian scietist was probably because there was so much bogus research done and even disinformation sowed around in those times. (Red sulphur was just lies, and Kirlian photography, ESP, telepathy, just to mention a few that I'd call wishful thinking, not science.)
Ricochet
1 / 5 (1) Dec 09, 2010
Not to mention that smoking was considered healthy back then...
KwasniczJ
2.3 / 5 (3) Dec 09, 2010
I guess the Russians reported the phenomena but it wasn't exactly published research.
It has been reported a much earlier, in 1930 with Russian J.W. Obreimoff in English press.

http://rspa.royal...full.pdf

http://skullsinth...ch-tape/
KwasniczJ
1 / 5 (4) Dec 09, 2010
..another reason why nobody believed the Russian scietist was probably because there was so much bogus research done and even disinformation sowed around in those time..

Who cares - if someone observed/predicted the effect first, the scientific priority should be attributed to him with no mercy (compare the Stigler's law of eponymy in this connection).

http://en.wikiped..._eponymy

Actually just this phenomena was reviewed thoroughly before WWWII already - so we can be sure, the trolls, who are claiming, they found X-ray in adhesive tape in 2008 weren't first in any way.

N.E. Harvey, "The luminescence of adhesive tape," Science 89 (1939), 460-461.
KwasniczJ
1.8 / 5 (5) Dec 09, 2010
The finding of fractal patterns during peeling of polymer layers is not original too.

http://www.britis...ente.jpg
sstritt
1 / 5 (2) Dec 09, 2010
I wonder if shipping department people are getting a significant extra radiation dose, they go through a lot of that tape.

Only if the shipping dept. is outside the ISS
Husky
not rated yet Dec 10, 2010
it wont be long before fractal patterns in dental plaque will be discovered and that grinding your teeth gives x-ray vision
Raveon
not rated yet Dec 10, 2010
I wonder if shipping department people are getting a significant extra radiation dose, they go through a lot of that tape.


My bad, missed the part about only in a vacuum. duh
fixer
not rated yet Dec 10, 2010
Send some to mythbusters! they built a bridge out of Duct tape so maybe they can build a teleporter or something out of this.
frajo
not rated yet Dec 11, 2010
Another reason why nobody believed the Russian scietist was probably because there was so much bogus research done and even disinformation sowed around in those times. (Red sulphur was just lies, and Kirlian photography, ESP, telepathy, just to mention a few that I'd call wishful thinking, not science.)
Which reminds me of the UFO "research" done elsewhere in those days.
Cheerio
not rated yet Dec 11, 2010
I think this is really cool. There are things that are happening in front of our very eyes, that we're only beginning to understand.

This is a very exciting time to be alive.

Now if only the tidal wave of knee-knocking Luddites can be weathered...
aroven
5 / 5 (1) Dec 16, 2010
Wow, this thread is a perfect example of why the rating system on this site is so broken. People are clearly giving any comment they don't personally agree with the lowest rating. And once you give somebody a 1 rating, it takes 5 more votes to get them back to 5 (I think). The idea that somebody can make a valid point, back it up with sources, and get a one rating is ridiculous. Way to stifle debate! I guess I'll just have to use this site for the articles and wait for them to be reposted to slashdot to enjoy the comments.
LKD
1 / 5 (2) Dec 23, 2010
Scotch tape is also a potent source of antiprotons for particle accelerators, and can be used to cure cancer and grow crops in the desert and cure AIDS.


That's duct tape. :D