Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

’Bumpy’ glass could lead to self-cleaning windows, slick micromachines

19.01.2005


Ohio State University engineers are designing super-slick, water-repellent surfaces that mimic the texture of lotus leaves.



The patent-pending technology could lead to self-cleaning glass, and could also reduce friction between the tiny moving parts inside microdevices.

Scientists have long known that the lotus, or water lily, makes a good model for a water-repellent surface, explained Bharat Bhushan, Ohio Eminent Scholar and the Howard D. Winbigler Professor of mechanical engineering at Ohio State. The leaf is waxy and covered with tiny bumps, so water rolls off.


In studying the lotus leaf, Bhushan realized that the same texture could be exploited to reduce friction between moving parts on machines. Small machines, such as those under development in the fields of micro- and nanotechnology, can’t be lubricated by normal means, and would especially benefit from the technology. “In general, what’s good for water-repellency is good for fighting friction,” Bhushan said.

But when it comes to designing high-tech surfaces -- for instance, a water-repellent car windshield or a low-friction joint on a micromachine -- just copying a lotus leaf isn’t enough. Bumpy, waxy surfaces can actually become sticky under some circumstances. “What people don’t know is what kind of surface is optimal,” he said. So he and his colleagues have built the first computer model that calculates the best bumpy surface for different materials and applications.

With the right kind of texture, manufacturers could make self-cleaning windows. Because the bumps would measure only a few nanometers (millionths of a meter) high, and would be made of a transparent material, the window would look like any other but still repel water and dirt. That would mean less window cleaning in homes and businesses.

So far, Bhushan’s team has focused on modeling bumps of different sizes and shapes. All the bumps included in the model aid water repellency by keeping water droplets from directly touching the surface.

Because the bumps are so much smaller than a droplet and so close together, they can’t puncture the droplet. In fact, if the droplet were perfectly balanced, it would just lie on the bumps the way a person can safely lie on a bed of nails. Bhushan’s model calculates how and where to place the bumps so that the droplet will contact the surface in just the right way to roll off.

In automobiles, water-repellent glass would improve safety by helping drivers see better, especially during inclement weather.

Right now, drivers can spray coatings on car windows to accomplish much the same thing, but those coatings wear off. Because the new technology builds water-repellency into the surface of the window, it would continue to work for the lifetime of the window.

Though drivers may rejoice at the idea of less window cleaning, Bhushan is most excited about what his technology could do for microelectronics. In 2001, his team developed the first direct method for measuring the friction between moving parts inside micromachines, and he has since been working on methods to reduce that friction.

Some of Bhushan’s industrial partners are building light-based electronics in which tiny mirrors move to reflect light in different directions. Others are working on very small sensors that detect and process chemical samples. Both kinds of devices are too small to use traditional lubricants on the moving parts.

One way to eliminate the need for lubricant is to build slick surfaces onto each individual part. Bhushan suspects his lotus-leaf surfaces might do the job. Manufacturers would just have to use his model to figure out what size and shape bumps are best for their application.

Bhushan has been supporting this work with his own internal laboratory funds, and he’ll need an industrial partner to carry the work further. He wants to fabricate some very high-quality textured materials for scientific study, so he’ll have to buy time in a clean room facility -- the kind computer chip manufacturers use.

Bharat Bhushan | EurekAlert!
Further information:
http://www.osu.edu

More articles from Materials Sciences:

nachricht Glass's off-kilter harmonies
18.01.2017 | University of Texas at Austin, Texas Advanced Computing Center

nachricht Explaining how 2-D materials break at the atomic level
18.01.2017 | Institute for Basic Science

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland

19.01.2017 | Earth Sciences

Not of Divided Mind

19.01.2017 | Life Sciences

Molecule flash mob

19.01.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>