Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New adhesive device could let humans walk on walls

02.02.2010
Could humans one day walk on walls, like Spider-Man? A palm-sized device invented at Cornell that uses water surface tension as an adhesive bond just might make it possible.

The rapid adhesion mechanism could lead to such applications as shoes or gloves that stick and unstick to walls, or Post-it-like notes that can bear loads, according to Paul Steen, professor of chemical and biomolecular engineering, who invented the device with Michael Vogel, a former postdoctoral associate.

The device is the result of inspiration drawn from a beetle native to Florida, which can adhere to a leaf with a force 100 times its own weight, yet also instantly unstick itself. Research behind the device is published online Feb. 1 in Proceedings of the National Academy of Sciences.

The device consists of a flat plate patterned with holes, each on the order of microns (one-millionth of a meter). A bottom plate holds a liquid reservoir, and in the middle is another porous layer. An electric field applied by a common 9-volt battery pumps water through the device and causes droplets to squeeze through the top layer. The surface tension of the exposed droplets makes the device grip another surface – much the way two wet glass slides stick together.

"In our everyday experience, these forces are relatively weak," Steen said. "But if you make a lot of them and can control them, like the beetle does, you can get strong adhesion forces."

For example, one of the researchers' prototypes was made with about 1,000 300-micron-sized holes, and it can hold about 30 grams – more than 70 paper clips. They found that as they scaled down the holes and packed more of them onto the device, the adhesion got stronger. They estimate, then, that a one-square-inch device with millions of 1-micron-sized holes could hold more than 15 pounds.

To turn the adhesion off, the electric field is simply reversed, and the water is pulled back through the pores, breaking the tiny "bridges" created between the device and the other surface by the individual droplets.

The research builds on previously published work that demonstrated the efficacy of what's called electro-osmotic pumping between surface tension-held interfaces, first by using just two larger water droplets.

One of the biggest challenges in making these devices work, Steen said, was keeping the droplets from coalescing, as water droplets tend to do when they get close together. To solve this, they designed their pump to resist water flow while it's turned off.

Steen envisions future prototypes on a grander scale, once the pump mechanism is perfected, and the adhesive bond can be made even stronger. He also imagines covering the droplets with thin membranes – thin enough to be controlled by the pump but thick enough to eliminate wetting. The encapsulated liquid could exert simultaneous forces, like tiny punches.

"You can think about making a credit card-sized device that you can put in a rock fissure or a door, and break it open with very little voltage," Steen said. "It's a fun thing to think about."

The research was funded primarily by the Defense Advanced Research Projects Agency and also by the National Science Foundation.

Blaine Friedlander | EurekAlert!
Further information:
http://www.cornell.edu

More articles from Life Sciences:

nachricht Study shines light on brain cells that coordinate movement
26.06.2017 | University of Washington Health Sciences/UW Medicine

nachricht New insight into a central biological dogma on ion transport
26.06.2017 | Aarhus University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Study shines light on brain cells that coordinate movement

26.06.2017 | Life Sciences

Smooth propagation of spin waves using gold

26.06.2017 | Physics and Astronomy

Switchable DNA mini-machines store information

26.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>