Hierarchical nano- and microstructures transform sheets of platinum, titanium and brass into light absorbing, water repelling, self-cleaning superstars
By zapping ordinary metals with femtosecond laser pulses researchers from the University of Rochester in New York have created extraordinary new surfaces that efficiently absorb light, repel water and clean themselves. The multifunctional materials could find use in durable, low maintenance solar collectors and sensors.
“This is the first time that a multifunctional metal surface is created by lasers that is superhydrophobic (water repelling), self-cleaning, and highly absorptive,” said Chunlei Guo, a physicist at the Institute of Optics at the University of Rochester who made the new surfaces with his colleague and fellow University of Rochester researcher Anatoliy Vorobyev. The researchers describe the laser-patterned surfaces in an article published in the Journal of Applied Physics, from AIP Publishing.
Enhanced light absorption will benefit technologies that require light collection, such as sensors and solar power devices, while superhydrophobicity will make a surface rust-resistant, anti-icing and anti-biofouling, all of which could help make such devices more robust and easier to maintain, Guo said. The superhydrophobic surfaces can also clean themselves, since water droplets repelled from the surface carry away dust particles very efficiently.
The researchers created the surfaces by zapping platinum, titanium and brass samples with extremely short femtosecond laser pulses that lasted on the order of a millionth of a billionth of a second. “During its short burst the peak power of the laser pulse is equivalent to that of the entire power grid of North America,” Guo said.
These extra-powerful laser pulses produced microgrooves, on top of which densely populated, lumpy nanostructures were formed. The structures essentially alter the optical and wetting properties of the surfaces of the three metals, turning the normally shiny surfaces velvet black (very optically absorptive) and also making them water repellent.
Most commercially used hydrophobic and high optical absorption materials rely on chemical coatings that can degrade and peel off over time, said Guo. Because the nano- and microstructures created by the lasers are intrinsic to the metal, the properties they confer should not deteriorate, he said.
The hydrophobic properties of the laser-patterned metals also compare favorably with a famous non-stick coating. “Many people think of Teflon as a hydrophobic surface, but if you want to get rid of water from a Teflon surface, you will have to tilt the surface to nearly 70 degrees before the water can slide off,” Guo said. “Our surface has a much stronger hydrophobicity and requires only a couple of degrees of tilt for water to slide off.”
Guo and his colleagues have a lot of experience changing the properties of materials with lasers. A couple of years ago, they used lasers to create a superhydrophilic (water attracting) surface that was so strong that water ran uphill against gravity. “After that, we were motivated to create the counterpart technology, making a surface to repel water,” Guo said.
The team has plans to work on creating multifunctional effects on other materials, such as semiconductors and dielectrics. The multifunctional effects should find a wide range of applications such as making better solar energy collectors.
The article, "Multifunctional surfaces produced by femtosecond laser pulses,” is authored by A. Y. Vorobyev and Chunlei Guo. It will be published in the Journal of Applied Physics on January 20, 2015 (DOI: 10.1063/1.4905616). After that date, it can be accessed at: http://scitation.aip.org/content/aip/journal/jap/117/3/10.1063/1.4905616
The authors of this paper are affiliated with the University of Rochester.
ABOUT THE JOURNAL
Journal of Applied Physics is an influential international journal publishing significant new experimental and theoretical results of applied physics research. See: http://jap.aip.org
Jason Socrates Bardi
American Institute of Physics
Jason Socrates Bardi | newswise
Custom sequences for polymers using visible light
22.03.2018 | Tokyo Metropolitan University
The search for dark matter widens
21.03.2018 | American Institute of Physics
An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.
The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.
In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...
19.03.2018 | Event News
16.03.2018 | Event News
13.03.2018 | Event News
22.03.2018 | Trade Fair News
22.03.2018 | Earth Sciences
22.03.2018 | Earth Sciences