Navigation Links
Cleaning with sunlight
Date:7/17/2012

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 faades 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 Verghl, 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.


'/>"/>

Contact: Dr. Michael Vergoehl
michael.vergoehl@ist.fraunhofer.de
49-531-215-5640
Fraunhofer-Gesellschaft
Source:Eurekalert  

Related biology news :

1. New paper by Notre Dame researchers describes method for cleaning up nuclear waste
2. Eddies, not sunlight, spur annual bloom of tiny plants in North Atlantic
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Cleaning with sunlight
(Date:4/24/2017)... 24, 2017 Janice Kephart , ... Identity Strategy Partners, LLP (IdSP) , today issues ... President Trump,s March 6, 2017 Executive Order: ... vetting can be instilled with greater confidence, enabling ... all refugee applications are suspended by until at ...
(Date:4/13/2017)... , April 13, 2017 UBM,s Advanced ... will feature emerging and evolving technology through ... Innovation Summits will run alongside the expo portion of ... sessions, panels and demonstrations focused on trending topics within ... advanced design and manufacturing event will take place June ...
(Date:4/11/2017)... 2017 No two people are believed ... New York University Tandon School of Engineering and ... that partial similarities between prints are common enough ... phones and other electronic devices can be more ... lies in the fact that fingerprint-based authentication systems ...
Breaking Biology News(10 mins):
(Date:6/20/2017)... (PRWEB) , ... June 20, 2017 , ... ... Linda Robbie, PhD, a well-versed leader with extensive assay development and biomarker expertise, ... Cambridge Biomedical is a Boston CRO specializing in bio-analytical assay development and sample ...
(Date:6/19/2017)... ... June 19, 2017 , ... As Vice President, Product ... including training, implementation, support, and client process and SOP development. , Mr. Guinter ... held leadership roles for service providers and top-tier pharmaceuticals, and as an independent ...
(Date:6/19/2017)... ... , ... A colony of healthy honey bees is like a superorganism--individual bees ... nectar containing nutrients necessary for growth and survival. Better nutrition gives the colony a ... to a decline in honey bee health. Sick and weakened bees diminish the colony's ...
(Date:6/16/2017)... ... 2017 , ... CTNext , Connecticut’s go-to resource for entrepreneurial support, today ... at Chelsea Piers in Stamford. , Nine finalists, all of whom are Connecticut-based companies ... opportunity to secure $10,000 awards to help support business growth. The winners included:, ...
Breaking Biology Technology: