I always like a good story about Namib desert beetles (Stenocara) and their water-recovering and repelling ways (Nov. 20, 2012 posting and June 13, 2014 posting) and this one comes courtesy of a July 24, 2014 news item on Nanowerk which provides an introduction to the beetle (Note: A link has been removed),
In the Namib Desert of Africa, the fog-filled morning wind carries the drinking water for a beetle called the Stenocara.
Tiny droplets collect on the beetle’s bumpy back. The areas between the bumps are covered in a waxy substance that makes them water-repellant, or hydrophobic (water-fearing). Water accumulates on the water-loving, or hydrophilic, bumps, forming droplets that eventually grow too big to stay put, then roll down the waxy surface.
The beetle slakes its thirst by tilting its back end up and sipping from the accumulated droplets that fall into its mouth. Incredibly, the beetle gathers enough water through this method to drink 12 percent of its body weight each day.
More than a decade ago, news of this creature’s efficient water collection system inspired engineers to try and reproduce these surfaces in the lab (“Water capture by a desert beetle”).
A July 24, 2014 US National Science Foundation (NSF) Discoveries article, which originated the news item, presents a comprehensive view of the NSF-funded research inspired by the Namib desert beetle (Note: Links have been removed),
What researchers have done is create surfaces that so excel at repelling or attracting water they’ve added a “super” at the front of their description: superhydrophobic or superhydrophilic.
“We can now do things with fluids we only imagined before,” says mechanical engineer Constantine Megaridis at the University of Illinois at Chicago. Megaridis and his team have two NSF grants from the Engineering Directorate’s Division of Chemical, Bioengineering, Environmental and Transport Systems.
NBD Nanotechnologies, a Boston-based company funded by NSF’s Small Business Technology Transfer program, aims to scale up the durability and functionality of surface coatings for industrial use.
One of the most impactful applications for superhydrophobic or hydrophobic research is improved condensation efficiency. When water vapor condenses to a liquid, it typically forms a film. That film is a barrier between the vapor and the surface, making it more difficult for other droplets to form. If that film can be prevented by whisking away droplets immediately after they condense–say, with a superhydrophobic surface–the rate of condensation increases.
Condensers are everywhere. They’re in your refrigerator, car and air conditioner. More efficient condensation would let all this equipment function with less energy. Better efficiency is especially important in places where large-scale cooling is paramount, such as power plants.
“NBD makes more durable coatings that span large surface areas,” says NBD Nanotechnologies senior scientist Sara Beaini. “Durability is an important factor, because when you’re working on the micro level you depend on having a pristine surface structure. Any mechanical or chemical abrasion that distorts the surface structures can significantly reduce or eliminate the advantageous surface properties quickly.”
NBD, which you might have guessed stands for Namib Beetle Design, has partnered with Megaridis and others to improve durability, the main challenge in commercializing superhydrophobic research. Power plant condensers with durable hydrophobic or superhydrophobic coatings could be more efficient. And with water and energy shortages looming, partnerships such as theirs that help to transfer this breakthrough from the lab to the outside world are increasingly valuable.
Kripa Varanasi, mechanical engineer at MIT and NSF CAREER awardee, has applied superhydrophobic coatings to metal, ceramics and glass, including the insides of ketchup bottles. Julie Crockett and Daniel Maynes at Brigham Young University developed extreme waterproofing by etching microscopic ridges or posts onto CD-sized wafers.
R Daniel Maynes
University of Illinois at Chicago
Iowa State University
Brigham Young University
NBD Nanotechnologies, Inc.
Massachusetts Institute of Technology
Ames , Iowa
Provo , Utah
Boston , Massachusetts
Chicago , Illinois
Thermal Transport Processes
#1235881 Convective Thermal Transport at Superhydrophobic Surfaces
#1066426 Investigation of icephobic behavior of surfaces with tunable properties
#1331817 STTR Phase I: STTR Proposal on Atmospheric Water Capture using Advanced Nanomaterials
#1066356 Turbulent Flow Drag Reduction Using Surfaces Exhibiting Superhydrophobicity and Riblets
#1235867 Collaborative Research: A Micropatterned Wettability Approach for Superior Boiling Heat Transfer Performance
#0952564 CAREER: Fundamental Studies of Condensation Phenomena on Heterogeneous and Hierarchical Nanoengineered Surfaces
The article also offers links to some of the articles and videos produced by the researchers.
Two comments, I can’t tell if the ‘NBD Nanotechnologies’ funding is included in the Related Awards section or in the Total Grants section. And, understandably, the NSF does not offer a comprehensive review of all the research being done in the US on the Namib desert beetle and water collection and waterproofing*. For example, as per my June 13, 2014 posting there is water collection research also inspired by the Namib beetle being done at Rice University and funded by the U.S. Department of Defense and the U.S. Air Force Office of Scientific Research.
Getting back to the NSF, the ‘Discoveries’ programme seems to stretch back to 2003 with a June 25, 2003 article ‘Discovery of Microbursts Leads to Safer Air Travel‘ being the first in this series. You can find out more about the NSF’s Discoveries programme (from its home page),
NSF’s public investment in science, engineering, education and technology helps to create knowledge and sustain prosperity. Read here about the Internet, microbursts, Web browsers, extrasolar planets, and more… a panoply of discoveries and innovations that began with NSF support.
This programme is a nice example of science communication/outreach accompanied by information about the funds awarded in an easily understood format. (In contrast, I was once given a listing of funds awarded to nanotechnology research in Canada over a two- or three-year period. I received a mass of data, some of it in Excel spreadsheets, some not. Briefly, it was a mess. This was not my sender’s fault; it was the Government of Canada’s official response to a question posed in Parliament.)
As far as I’m aware the NSF’s Discoveries programme is unique in its accessible explanations of the science and its revelation of the funding scientists receive from them. Bravo to the folks at the NSF for tying together and explaining the research and the various funds awarded to research in water recovery/collection and water proofing.
* ‘water proofing’ changed to ‘waterproofing’ on July 30, 2014.