Subscribe free to our newsletters via your
. 24/7 Space News .




TECH SPACE
Cleaning with sunlight
by Staff Writers
Braunschweig, Germany (SPX) Jul 18, 2012


Scientists are now hoping that they can solve this problem by incorporating titanium dioxide molecules in the plastic used to make the garden chair and adding a little bit of sunlight.

The sun breaks through the clouds - and surfaces start cleaning themselves! It may sound like magic, but in fact it's all thanks to the addition of titanium dioxide molecules. Activated by UV light, they trigger a reaction which destroys bacteria, algae and fungi, keeping items such as the armrests of garden chairs nice and clean.

Summer is just around the corner and it's time to dust off the garden tables and chairs. But garden furniture that has been left in the shade too long is often covered with a slimy film of algae, moss, bacteria and fungi which is difficult or even impossible to remove.

Scientists are now hoping that they can solve this problem by incorporating titanium dioxide molecules in the plastic used to make the garden chair and adding a little bit of sunlight.

When these titanium dioxide molecules are 'activated' by the UV light in the sun's rays, they act as a kind of catalyst, triggering an electrochemical reaction which produces free radicals.

These and other active molecules strike a fatal blow to bacteria, fungi and similar organisms, first destroying the cell walls and then penetrating the cytoplasm - the substance that fills the cell - and damaging the bacteria's DNA. As a result, the organic substances are destroyed instead of remaining stuck to the surface.

But just how well do these photocatalytic coatings work? What organic elements do they destroy, and what are they powerless against? These two questions have been the subject of investigation by researchers at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart.

"For example, we ran some outdoor tests on garden chair armrests with photocatalytic coatings and compared them to ones made from conventional plastic," says Dr. Iris Trick, group manager at the IGB.

Dr. Trick and her team sprayed the coated and uncoated armrests with a mixture of various bacteria, mosses, algae and fungi and then left them exposed to the weather for two years.

At the end of the test, it was almost impossible to remove the layer of dirt from the normal armrests - yet the armrests made from photocatalytic plastics were still almost completely clean and white, even after spending two years outside.

The researchers also tested the effectiveness of their special coatings on armrests and a range of other surfaces in the lab. To do this, they applied up to 30 different kinds of fungal, bacterial and algal cultures to coated and uncoated surfaces and compared how the cultures evolved.

In addition, they analyzed the degradation products generated on the self-cleaning surfaces by the electrochemical reaction.

Self-cleaning walls and displays
The opportunities offered by titanium dioxide molecules extend far beyond armrests. For example, researchers from the Fraunhofer Institute for Manufacturing Engineering and Automation IPA in Stuttgart are working on paints for building facades which contain titanium dioxide particles. If the wall gets dirty, the photocatalysis degrades the organic contaminants and the paint stays reasonably clean.

The scientists have even developed a self-cleaning coating for glass surfaces: "If you apply a thin coating of titanium dioxide to a glass surface such as a smartphone screen, the skin oils and fingerprints gradually disappear from the display by themselves," says Dr. Michael Vergohl, head of department at the Fraunhofer Institute for Surface Engineering and Thin Films IST in Braunschweig and head of the Fraunhofer Photocatalysis Alliance.

All that is needed is one hour of sunlight - unlike previous photocatalytic surfaces, which would have required the smartphone to be left in the sun for three days. The next step is to develop new materials that can also be activated by artificial light.

The Fraunhofer Photocatalysis Alliance is a group of ten Fraunhofer institutes which have decided to combine their expertise in this field. It covers the full spectrum of photocatalytic surface development and offers considerable know-how from a single source.

Research News July 2012 [ PDF 0,32 MB ]

.


Related Links
Fraunhofer
Space Technology News - Applications and Research






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle








TECH SPACE
"Sifting" Liquid at the Cellular Level
Philadelphia PA (SPX) Jul 18, 2012
Drexel University engineers continue to drive research into the use of carbon nanotubes, straw-like structures that are more than 1,000 times thinner than a single human hair. Their most recent development uses the tiny tubes to separate liquids within a solution. The researchers have shown that individual carbon nanotubes can act as a separation channel that would force two differing molecules ... read more


TECH SPACE
ESA to catch laser beam from Moon mission

Researchers Estimate Ice Content of Crater at Moon's South Pole

Researchers find evidence of ice content at the moon's south pole

Nanoparticles found in moon glass bubbles explain weird lunar soil behaviour

TECH SPACE
Opportunity Continues to Explore Rocks on the Rim of Endeavour Crater

Orbiter Enters, Then Exits, Standby Safe Mode

NASA's Mars rover two weeks from landing

Developing Technologies For Living Off the Land...In Space

TECH SPACE
Inflatable Spacecraft Heat Shield Set to Launch

Ambitious ISRO enhancing India's space capabilities

Titanic II to have 'safety deck': Australian tycoon

Me and My Spacesuit

TECH SPACE
Astronauts in good shape after return

Shenzhou mission sparks 'science fever'

China Beats Russia on Space Launches

China open to cooperation

TECH SPACE
Joyful crews unite aboard space station

Russian Space Lab Launch Delayed Again

Russian rocket launches new crew to space

Science, Maintenance for Station Crew; Launch Preps for New Crew Members

TECH SPACE
NASA Selects Launch Services Contract for Jason-3 Mission

NASA Selects Launch Services Contract for Three Missions

NASA Selects ULA's Workhorse Delta II Rocket for Three Future Missions

SpaceX Completes Design Review of Dragon

TECH SPACE
Can Astronomers Detect Exoplanet Oceans

The Mysterious Case of the Disappearing Dust

Study in Nature sheds new light on planet formation

New Instrument Sifts Through Starlight to Reveal New Worlds

TECH SPACE
Heat is Source of 'Pioneer Anomaly'

To Extinguish a Hot Flame, DARPA Studied Cold Plasma

Sailing with nerves of glass

Scientists from northern Germany produce the lightest material in the world




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement