Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Team explains 'the wallpaper problem'

01.04.2008
Work could have industrial applications

Frustrated by tape that won't peel off the roll in a straight line? Angry at wallpaper that refuses to tear neatly off the wall?

A new study reveals why these efforts can be so aggravating. Wallpaper is not out to foil you-it's just obeying the laws of physics, according to a team of researchers from the Centre National de la Recherche Scientifique (CNRS) in Paris, the Universidad de Santiago, Chile, and MIT.

The report, published in the March 30 online issue of Nature Materials, sheds light on a phenomenon many people have experienced, which the researchers dubbed “the wallpaper problem.”

“You want to redecorate your bedroom, so you yank down the wallpaper. You wish that the flap would tear all the way down to the floor, but it comes together in a triangle and you have to start all over again,” said Pedro Reis, one of the authors of the paper and an applied mathematics instructor at MIT.

This pattern, where two cracks propagate toward each other and meet at a point, is extremely robust. It applies not only to wallpaper but other adhesives such as tape, as well as nonadhesive plastic sheets such as the shrink-wrap that envelops compact discs. It even extends to fruit: The skin on a tomato or a grape typically forms a triangle when peeled off.

“This has happened to everyone. it's frustrating,” said Reis, who collaborated with Enrique Cerda and Eugenio Hamm of the Universidad de Santiago, Benoit Roman of CNRS and Michael LeBlanc of the University of Chicago.

The team found that those ubiquitous triangular tears arise from interactions between three inherent properties of adhesive materials: elasticity (stiffness), adhesive energy (how strongly the adhesive sticks to a surface) and fracture energy (how tough it is to rip).

The researchers developed a formulation that predicts the angle of the triangle formed, based on those three properties.

They also figured out just how those triangular tears arise. As the strip is pulled, energy builds up in the fold that forms where the tape is peeling from the surface. The tape can release that energy in two ways: by unpeeling from its surface and by becoming narrower, both of which it does.

In a possible industrial application, materials engineers could use this method to calculate one of the three key properties, if the other two are known. This could be particularly useful in microtechnologies, such as stretchable electronics, where the characterization of thin material properties is very difficult.

Reis, who now works in MIT's Applied Mathematics Laboratory, and his collaborators at CNRS and Universidad de Santiago got the idea for the project after noticing consistent tearing patterns in plastic sheets such as the plastic wrapping of CDs.

The researchers tried controlled experimental versions of the same process in their lab and got the same results. “This shape is really robust, so there must be something fundamental going on that gives rise to these shapes,” Reis said.

However, the shapes formed by tearing nonadhesive sheets proved difficult to study because they are not perfect triangles, and without adhesion, the physics of the problem is more complicated. Instead, the researchers turned their attention to adhesives, which do form perfect triangles when torn.

The triangular shapes can also be seen in the work of French artist Jacques Villeglé. His art consists of posters taken from the streets of Paris and other French cities, complete with the same sort of rips that the researchers studied. One of the posters may be featured on the cover of Nature Materials to illustrate the team's paper.

Torn posters, tape and tomato skins may seem like strange research topics for physicists and applied mathematicians, but it's perfectly normal to Reis and his colleagues, who draw inspiration from an array of everyday objects.

Such real-world applications are not only fun to study, but “we can really learn things that will be useful for industry and help us understand the everyday world around us. It is also a great way to motivate students to be interested in science,” Reis said.

Elizabeth Thomson | alfa
Further information:
http://www.mit.edu

More articles from Studies and Analyses:

nachricht The personality factor: How to foster the sharing of research data
06.09.2017 | ZBW – Leibniz-Informationszentrum Wirtschaft

nachricht Europe’s Demographic Future. Where the Regions Are Heading after a Decade of Crises
10.08.2017 | Berlin-Institut für Bevölkerung und Entwicklung

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Comet or asteroid? Hubble discovers that a unique object is a binary

21.09.2017 | Physics and Astronomy

Cnidarians remotely control bacteria

21.09.2017 | Life Sciences

Monitoring the heart's mitochondria to predict cardiac arrest?

21.09.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>