Tag Archives: superhydrophobic

Material that sheds like a snake when it’s damaged

Truly water-repellent materials are on the horizon. Or, they would be if one tiny problem was solved. According to a May  3, 2017 news item on ScienceDaily, scientists may have come up with that solution,

Imagine a raincoat that heals a scratch by shedding the part of the outer layer that’s damaged. To create such a material, scientists have turned to nature for inspiration. They report in ACS’ journal Langmuir a water-repellant material that molts like a snake’s skin when damaged to reveal another hydrophobic [water-repellent] layer beneath it.

A May 3, 2017 American Chemical Society (ACS) press release (also on EurekAlert), which originated the news item, expands on the theme,

Lotus leaves, water striders and other superhydrophobic examples from nature have inspired scientists to copy their water-repelling architecture to develop new materials. Such materials are often made by coating a substrate with nanostructures, which can be shored up by adding microstructures to the mix. Superhydrophobic surfaces could be useful in a range of applications including rain gear, medical instruments and self-cleaning car windows. But most of the prototypes so far haven’t been strong enough to stand up to damage by sharp objects. To address this shortcoming, Jürgen Rühe and colleagues again found a potential solution in nature — in snake and lizard skins.

The researchers stacked three layers to create their material: a water-repellant film made with poly-1H,1H,2H,2H-perfluorodecyl acrylate (PFA) “nanograss” on the top, a water-soluble polymer in the middle and a superhydrophobic silicon nanograss film on the bottom. Nanograss consists of tiny needle-like projections sticking straight up. The team scratched the coating and submerged the material in water, which then seeped into the cut and dissolved the polymer. The top layer then peeled off like molted skin and floated away, exposing the bottom, water-repellant film. Although further work is needed to strengthen the top coating so that a scratch won’t be able to penetrate all three layers, the researchers say it offers a new approach to creating self-cleaning and water-repellant materials.

The authors acknowledge support from the German Federal Ministry of Education and Research (BMBF) and VDI/VDE/IT GmbH through project NanoTau.

Here’s a video demonstrating the concept,

Published on May 2, 2017

Scientists turn to snakes and lizards for inspiration to create a new material that sheds its outer layer when scratched.

Finally, a link to and a citation for the paper,

Molting Materials: Restoring Superhydrophobicity after Severe Damage via Snakeskin-like Shedding by Roland Hönes, Vitaliy Kondrashov, and Jürgen Rühe. Langmuir, Article ASAP DOI: 10.1021/acs.langmuir.7b00814 Publication Date (Web): April 14, 2017

Copyright © 2017 American Chemical Society

This paper is behind a paywall.

A new Shrinky Dinks story: super-wrinkled and super-crumpled graphene for self-cleaning surfaces and other applications

Caption: Wrinkles and crumples, introduced by placing graphene on shrinky polymers, can enhance graphene's properties. Credit: Hurt and Wong Labs / Brown University

Caption: Wrinkles and crumples, introduced by placing graphene on shrinky polymers, can enhance graphene’s properties. Credit: Hurt and Wong Labs / Brown University

A March 21, 2016 news item on ScienceDaily describes how Brown University (US) researchers developed super-wrinkled and super-crumpled graphene,

Crumple a piece of paper and it’s probably destined for the trash can, but new research shows that repeatedly crumpling sheets of the nanomaterial graphene can actually enhance some of its properties. In some cases, the more crumpled the better.

The research by engineers from Brown University shows that graphene, wrinkled and crumpled in a multi-step process, becomes significantly better at repelling water–a property that could be useful in making self-cleaning surfaces. Crumpled graphene also has enhanced electrochemical properties, which could make it more useful as electrodes in batteries and fuel cells.

A March 21, 2016 Brown University news release (also on EurekAlert), which originated the news item, provides more detail about the current and previous research,

This new research builds on previous work done by Robert Hurt and Ian Wong, from Brown’s School of Engineering. The team had previously showed that by introducing wrinkles into graphene, they could make substrates for culturing cells that were more similar to the complex environments in which cells grow in the body. For this latest work, the researchers led by Po-Yen Chen, a Hibbit postdoctoral fellow, wanted to build more complex architectures incorporating both wrinkles and crumples. “I wanted to see if there was a way to create higher-generational structures,” Chen said.

To do that, the researchers deposited layers of graphene oxide onto shrink films–polymer membranes that shrink when heated (kids may know these as Shrinky Dinks [emphasis mine]). As the films shrink, the graphene on top is compressed, causing it to wrinkle and crumple. To see what kind of structures they could create, the researchers compressed same graphene sheets multiple times. After the first shrink, the film was dissolved away, and the graphene was placed in a new film to be shrunk again.

The researchers experimented with different configurations in the successive generations of shrinking. For example, sometimes they clamped opposite ends of the films, which caused them to shrink only along one axis. Clamped films yielded graphene sheets with periodic, basically parallel wrinkles across its surface. Unclamped films shrank in two dimensions, both length- and width-wise, creating a graphene surface that was crumpled in random shapes.

The team experimented with those different modes of shrinking over three successive generations. For example, they might shrink the same graphene sheet on a clamped film, then an unclamped film, then clamped again; or unclamped, clamped, unclamped. They also rotated the graphene in different configurations between shrinkings, sometimes placing the sheet perpendicular to its original orientation.

The team found that the multi-generational approach could substantially compress the graphene sheets, making them as small as one-fortieth their original size. They also showed that successive generations could create interesting patterns along the surface–wrinkles and crumples that were superimposed onto each other, for example.

“As you go deeper into the generations you tend to get larger wavelength structures with the original, smaller wavelength structure from earlier generations built into them,” said Robert Hurt, a professor of engineering at Brown and one of the paper’s corresponding authors.

A sheet that was shrunk clamped, unclamped, and then clamped looked different from ones that were unclamped, clamped, unclamped, for example.

“The sequence matters,” said Wong, also a corresponding author on the paper. “It’s not like multiplication where 2 times 3 is the same as 3 times 2. The material has a ‘memory’ and we get different results when we wrinkle or crumple in a different order.”

The researchers generated a kind of taxonomy of structures born from different shrinking configurations. They then tested several of those structures to see how they altered the properties of the graphene sheets.

Enhanced properties

They showed that a highly crumpled graphene surface becomes superhydrophobic–able to resist wetting by water. When water touches a hydrophobic surface, it beads up and rolls off. When the contact angle of those water beads with an underlying surface exceeds 160 degrees–meaning very little of the water bead’s surface touches the material–the material is said to be superhydrophobic. The researchers showed that they could make superhydrophobic graphene with three unclamped shrinks.

The team also showed that crumpling could enhance the electrochemical behaviors of graphene, which could be useful in next-generation energy storage and generation. The research showed that crumpled graphene used as a battery electrode had as much as a 400 percent increase in electrochemical current density over flat graphene sheets. That increase in current density could make for vastly more efficient batteries.

“You don’t need a new material to do it,” Chen said. “You just need to crumple the graphene.”

In additional to batteries and water resistant coatings, graphene compressed in this manner might also be useful in stretchable electronics–a wearable sensor, for example.

The group plans to continue experimenting with different ways of generating structures on graphene and other nanomaterials.

“There are many new two-dimensional nanomaterials that have interesting properties, not just graphene,” Wong said. “So other materials or combinations of materials may also organize into interesting structures with unexpected functionalities.”

Here’s a link to and a citation for the paper,

Multiscale Graphene Topographies Programmed by Sequential Mechanical Deformation by Po-Yen Chen, Jaskiranjeet Sodhi, Yang Qiu, Thomas M. Valentin, Ruben Spitz Steinberg, Zhongying Wang, Robert H. Hurt, and Ian Y. Wong. Advanced Materials DOI: 10.1002/adma.201506194 Article first published online: 21 MAR 2016

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

As for Shrinky Dinks, I first featured this material and its use in science research in an Aug. 16, 2010 posting about Shrinky Dinks and nanopatterning. It was originally developed by Betty J. Morris as craft material for children. Both she and the scientist kindly answered some followup questions inspired by the original news release and published in the 2010 post.

Commercializing nanotechnology: Peter Thiel’s Breakout Labs and Argonne National Laboratories

Breakout Labs

I last wrote about entrepreneur Peter Thiel’s Breakout Labs project in an Oct. 26, 2011 posting announcing its inception. An Oct. 6, 2015 Breakout Labs news release (received in my email) highlights a funding announcement for four startups of which at least three are nanotechnology-enabled,

Breakout Labs, a program of Peter Thiel’s philanthropic organization, the Thiel Foundation, announced today that four new companies advancing scientific discoveries in biomedical, chemical engineering, and nanotechnology have been selected for funding.

“We’re always hearing about bold new scientific research that promises to transform the world, but far too often the latest discoveries are left withering in a lab,” said Lindy Fishburne, Executive Director of Breakout Labs. “Our mission is to help a new type of scientist-entrepreneur navigate the startup ecosystem and build lasting companies that can make audacious scientific discoveries meaningful to everyday life. The four new companies joining the Breakout Labs portfolio – nanoGriptech, Maxterial, C2Sense, and CyteGen – embody that spirit and we’re excited to be working with them to help make their vision a reality.”

The future of adhesives: inspired by geckos

Inspired by the gecko’s ability to scuttle up walls and across ceilings due to their millions of micro/nano foot-hairs,nanoGriptech (http://nanogriptech.com/), based in Pittsburgh, Pa., is developing a new kind of microfiber adhesive material that is strong, lightweight, and reusable without requiring glues or producing harmful residues. Currently being tested by the U.S. military, NASA, and top global brands, nanoGriptech’s flagship product Setex™ is the first adhesive product of its kind that is not only strong and durable, but can also be manufactured at low cost, and at scale.

“We envision a future filled with no-leak biohazard enclosures, ergonomic and inexpensive car seats, extremely durable aerospace adhesives, comfortable prosthetic liners, high performance athletic wear, and widely available nanotechnology-enabled products manufactured less expensively — all thanks to the grippy little gecko,” said Roi Ben-Itzhak, CFO and VP of Business Development for nanoGriptech.

A sense of smell for the digital world

Despite the U.S. Department of Agriculture’s recent goals to drastically reduce food waste, most consumers don’t realize the global problem created by 1.3 billion metric tons of food wasted each year — clogging landfills and releasing unsustainable levels of methane gas into the atmosphere. Using technology developed at MIT’s Swager lab, Cambridge, Ma.-based C2Sense(http://www.c2sense.com/) is developing inexpensive, lightweight hand-held sensors based on carbon nanotubes which can detect fruit ripeness and meat, fish and poultry freshness. Smaller than a half of a business card, these sensors can be developed at very low cost, require very little power to operate, and can be easily integrated into most agricultural supply chains, including food storage packaging, to ensure that food is picked, stored, shipped, and sold at optimal freshness.

“Our mission is to bring a sense of smell to the digital world. With our technology, that package of steaks in your refrigerator will tell you when it’s about to go bad, recommend some recipe options and help build out your shopping list,” said Jan Schnorr, Chief Technology Officer of C2Sense.

Amazing metals that completely repel water

MaxterialTM, Inc. develops amazing materials that resist a variety of detrimental environmental effects through technology that emulates similar strategies found in nature, such as the self-cleaning lotus leaf and antifouling properties of crabs. By modifying the surface shape or texture of a metal, through a method that is very affordable and easy to introduce into the existing manufacturing process, Maxterial introduces a microlayer of air pockets that reduce contact surface area. The underlying material can be chemically the same as ever, retaining inherent properties like thermal and electrical conductivity. But through Maxterial’s technology, the metallic surface also becomes inherently water repellant. This property introduces the superhydrophobic maxterial as a potential solution to a myriad of problems, such as corrosion, biofouling, and ice formation. Maxterial is currently focused on developing durable hygienic and eco-friendly anti-corrosion coatings for metallic surfaces.

“Our process has the potential to create metallic objects that retain their amazing properties for the lifetime of the object – this isn’t an aftermarket coating that can wear or chip off,” said Mehdi Kargar, Co-founder and CEO of Maxterial, Inc. “We are working towards a day when shipping equipment can withstand harsh arctic environments, offshore structures can resist corrosion, and electronics can be fully submersible and continue working as good as new.”

New approaches to combat aging

CyteGen (http://cytegen.com/) wants to dramatically increase the human healthspan, tackle neurodegenerative diseases, and reverse age-related decline. What makes this possible now is new discovery tools backed by the dream team of interdisciplinary experts the company has assembled. CyteGen’s approach is unusually collaborative, tapping into the resources and expertise of world-renowned researchers across eight major universities to focus different strengths and perspectives to achieve the company’s goals. By approaching aging from a holistic, systematic point of view, rather than focusing solely on discrete definitions of disease, they have developed a new way to think about aging, and to develop treatments that can help people live longer, healthier lives.

“There is an assumption that aging necessarily brings the kind of physical and mental decline that results in Parkinson’s, Alzheimer’s, and other diseases. Evidence indicates otherwise, which is what spurred us to launch CyteGen,” said George Ugras, Co-Founder and President of CyteGen.

To date, Breakout Labs has invested in more than two dozen companies at the forefront of science, helping radical technologies get beyond common hurdles faced by early stage companies, and advance research and development to market much more quickly. Portfolio companies have raised more than six times the amount of capital invested in the program by the Thiel Foundation, and represent six Series A valuations ranging from $10 million to $60 million as well as one acquisition.

You can see the original Oct. 6, 2015 Breakout Labs news release here or in this Oct. 7, 2015 news item on Azonano.

Argonne National Labs and Nano Design Works (NDW) and the Argonne Collaborative Center for Energy Storage Science (ACCESS)

The US Department of Energy’s Argonne National Laboratory’s Oct. 6, 2015 press release by Greg Cunningham announced two initiatives meant to speed commercialization of nanotechnology-enabled products for the energy storage and other sectors,

Few technologies hold more potential to positively transform our society than energy storage and nanotechnology. Advances in energy storage research will revolutionize the way the world generates and stores energy, democratizing the delivery of electricity. Grid-level storage can help reduce carbon emissions through the increased adoption of renewable energy and use of electric vehicles while helping bring electricity to developing parts of the world. Nanotechnology has already transformed the electronics industry and is bringing a new set of powerful tools and materials to developers who are changing everything from the way energy is generated, stored and transported to how medicines are delivered and the way chemicals are produced through novel catalytic nanomaterials.

Recognizing the power of these technologies and seeking to accelerate their impact, the U.S. Department of Energy’s Argonne National Laboratory has created two new collaborative centers that provide an innovative pathway for business and industry to access Argonne’s unparalleled scientific resources to address the nation’s energy and national security needs. These centers will help speed discoveries to market to ensure U.S. industry maintains a lead in this global technology race.

“This is an exciting time for us, because we believe this new approach to interacting with business can be a real game changer in two areas of research that are of great importance to Argonne and the world,” said Argonne Director Peter B. Littlewood. “We recognize that delivering to market our breakthrough science in energy storage and nanotechnology can help ensure our work brings the maximum benefit to society.”

Nano Design Works (NDW) and the Argonne Collaborative Center for Energy Storage Science (ACCESS) will provide central points of contact for companies — ranging from large industrial entities to smaller businesses and startups, as well as government agencies — to benefit from Argonne’s world-class expertise, scientific tools and facilities.

NDW and ACCESS represent a new way to collaborate at Argonne, providing a single point of contact for businesses to assemble tailored interdisciplinary teams to address their most challenging R&D questions. The centers will also provide a pathway to Argonne’s fundamental research that is poised for development into practical products. The chance to build on existing scientific discovery is a unique opportunity for businesses in the nano and energy storage fields.

The center directors, Andreas Roelofs of NDW and Jeff Chamberlain of ACCESS, have both created startups in their careers and understand the value that collaboration with a national laboratory can bring to a company trying to innovate in technologically challenging fields of science. While the new centers will work with all sizes of companies, a strong emphasis will be placed on helping small businesses and startups, which are drivers of job creation and receive a large portion of the risk capital in this country.

“For a startup like mine to have the ability to tap the resources of a place like Argonne would have been immensely helpful,” said Roelofs. “We”ve seen the power of that sort of access, and we want to make it available to the companies that need it to drive truly transformative technologies to market.”

Chamberlain said his experience as an energy storage researcher and entrepreneur led him to look for innovative approaches to leveraging the best aspects of private industry and public science. The national laboratory system has a long history of breakthrough science that has worked its way to market, but shortening that journey from basic research to product has become a growing point of emphasis for the national laboratories over the past couple of decades. The idea behind ACCESS and NDW is to make that collaboration even easier and more powerful.

“Where ACCESS and NDW will differ from the conventional approach is through creating an efficient way for a business to build a customized, multi-disciplinary team that can address anything from small technical questions to broad challenges that require massive resources,” Chamberlain said. “That might mean assembling a team with chemists, physicists, computer scientists, materials engineers, imaging experts, or mechanical and electrical engineers; the list goes on and on. It’s that ability to tap the full spectrum of cross-cutting expertise at Argonne that will really make the difference.”

Chamberlain is deeply familiar with the potential of energy storage as a transformational technology, having led the formation of Argonne’s Joint Center for Energy Storage Research (JCESR). The center’s years-long quest to discover technologies beyond lithium-ion batteries has solidified the laboratory’s reputation as one of the key global players in battery research. ACCESS will tap Argonne’s full battery expertise, which extends well beyond JCESR and is dedicated to fulfilling the promise of energy storage.

Energy storage research has profound implications for energy security and national security. Chamberlain points out that approximately 1.3 billion people across the globe do not have access to electricity, with another billion having only sporadic access. Energy storage, coupled with renewable generation like solar, could solve that problem and eliminate the need to build out massive power grids. Batteries also have the potential to create a more secure, stable grid for countries with existing power systems and help fight global climate disruption through adoption of renewable energy and electric vehicles.

Argonne researchers are pursuing hundreds of projects in nanoscience, but some of the more notable include research into targeted drugs that affect only cancerous cells; magnetic nanofibers that can be used to create more powerful and efficient electric motors and generators; and highly efficient water filtration systems that can dramatically reduce the energy requirements for desalination or cleanup of oil spills. Other researchers are working with nanoparticles that create a super-lubricated state and other very-low friction coatings.

“When you think that 30 percent of a car engine’s power is sacrificed to frictional loss, you start to get an idea of the potential of these technologies,” Roelofs said. “But it’s not just about the ideas already at Argonne that can be brought to market, it’s also about the challenges for businesses that need Argonne-level resources. I”m convinced there are many startups out there working on transformational ideas that can greatly benefit from the help of a place Argonne to bring those ideas to fruition. That is what has me excited about ACCESS and NDW.”

For more information on ACCESS, see: access.anl.gov

For more information on NDW, see: nanoworks.anl.gov

You can read more about the announcement in an Oct. 6, 2015 article by Greg Watry for R&D magazine featuring an interview with Andreas Roelofs.

Pancake bounce

What impact does a droplet make on a solid surface? It’s not the first question that comes to my mind but scientists have been studying it for over a century. From an Aug. 5, 2015 news item on Nanowerk (Note: A link has been removed),

Studies of the impact a droplet makes on solid surfaces hark back more than a century. And until now, it was generally believed that a droplet’s impact on a solid surface could always be separated into two phases: spreading and retracting. But it’s much more complex than that, as a team of researchers from City University of Hong Kong, Ariel University in Israel, and Dalian University of Technology in China report in the journal Applied Physics Letters, from AIP Publishing (“Controlling drop bouncing using surfaces with gradient features”).

An Aug. 4, 2015 American Institute of Physics news release (also on EurekAlert), which originated the news item, describes the impact in detail,

“During the spreading phase, the droplet undergoes an inertia-dominant acceleration and spreads into a ‘pancake’ shape,” explained Zuankai Wang, an associate professor within the Department of Mechanical and Biomedical Engineering at the City University of Hong Kong. “And during the retraction phase, the drop minimizes its surface energy and pulls back inward.”

Remarkably, on gold standard superhydrophobic–a.k.a. repellant–surfaces such as lotus leaves, droplets jump off at the end of the retraction stage due to the minimal energy dissipation during the impact process. This is attributed to the presence of an air cushion within the rough surface.

There exists, however, a classical limit in terms of the contact time between droplets and the gold standard superhydrophobic materials inspired by lotus leaves.

As the team previously reported in the journal Nature Physics, it’s possible to shape the droplet to bounce from the surface in a pancake shape directly at the end of the spreading stage without going through the receding process. As a result, the droplet can be shed away much faster.

“Interestingly, the contact time is constant under a wide range of impact velocities,” said Wang. “In other words: the contact time reduction is very efficient and robust, so the novel surface behaves like an elastic spring. But the real magic lies within the surface texture itself.”

To prevent the air cushion from collapsing or water from penetrating into the surface, conventional wisdom suggests the use of nanoscale posts with small inter-post spacings. “The smaller the inter-post spacings, the greater the impact velocity the small inter-post can withstand,” he elaborated. “By contrast, designing a surface with macrostructures–tapered sub-millimeter post arrays with a wide spacing–means that a droplet will shed from it much faster than any previously engineered materials.”

What the New Results Show

Despite exciting progress, rationally controlling the contact time and quantitatively predicting the critical Weber number–a number used in fluid mechanics to describe the ratio between deforming inertial forces and stabilizing cohesive forces for liquids flowing through a fluid medium–for the occurrence of pancake bouncing remained elusive.

So the team experimentally demonstrated that the drop bouncing is intricately influenced by the surface morphology. “Under the same center-to-center post spacing, surfaces with a larger apex angle can give rise to more pancake bouncing, which is characterized by a significant contact time reduction, smaller critical Weber number, and a wider Weber number range,” according to co-authors Gene Whyman and Edward Bormashenko, both professors at Ariel University.

Wang and colleagues went on to develop simple harmonic spring models to theoretically reveal the dependence of timescales associated with the impinging drop and the critical Weber number for pancake bouncing on the surface morphology. “The insights gained from this work will allow us to rationally design various surfaces for many practical applications,” he added.

The team’s novel surfaces feature a shortened contact time that prevents or slows ice formation. “Ice formation and its subsequent buildup hinder the operation of modern infrastructures–including aircraft, offshore oil platforms, air conditioning systems, wind turbines, power lines, and telecommunications equipment,” Wang said.

At supercooled temperatures, which involves lowering the temperature of a liquid or gas below its freezing point without it solidifying, the longer a droplet remains in contact with a surface before bouncing off the greater the chances are of it freezing in place. “Our new surface structure can be used to help prevent aircraft wings and engines from icing,” he said.

This is highly desirable, because a very light coating of snow or ice–light enough to be barely visible–is known to reduce the performance of airplanes and even cause crashes. One such disaster occurred in 2009, and called attention to the dangers of in-flight icing after it caused Air France Flight 447 flying from Rio de Janeiro to Paris to crash into the Atlantic Ocean.

Beyond anti-icing for aircraft, “turbine blades in power stations and wind farms can also benefit from an anti-icing surface by gaining a boost in efficiency,” he added.

As you can imagine, this type of nature-inspired surface shows potential for a tremendous range of other applications as well–everything from water and oil separation to disease transmission prevention.

The next step for the team? To “develop bioinspired ‘active’ materials that are adaptive to their environments and capable of self-healing,” said Wang.

Here’s a link to and a citation for the paper,

Controlling drop bouncing using surfaces with gradient features by Yahua Liu, Gene Whyman, Edward Bormashenko, Chonglei Hao, and Zuankai Wang. Appl. Phys. Lett. 107, 051604 (2015); http://dx.doi.org/10.1063/1.4927055

This paper appears to be open access.

Finally, here’s an illustration of the pancake bounce,

Droplet hitting tapered posts shows “pancake” bouncing characterized by lifting off the surface of the end of spreading without retraction. Credit- Z.Wang/HKU

Droplet hitting tapered posts shows “pancake” bouncing characterized by lifting off the surface of the end of spreading without retraction. Credit- Z.Wang/HKU

There is also a pancake bounce video which you can view here on EurekAlert.

How geckos self-clean, even in dusty environments

An Australian research team claims a world first with regard to ‘gecko research’ according to a March 16, 2015* news item on ScienceDaily,

In a world first, a research team including James Cook University [JCU] scientists has discovered how geckos manage to stay clean, even in dusty deserts.

The process, described in Interface, a journal of the Royal Society, may also turn out to have important human applications.

JCU’s Professor Lin Schwarzkopf said the group found that tiny droplets of water on geckos, for instance from condensing dew, come into contact with hundreds of thousands of extremely small hair-like spines that cover the animals’ bodies.

A March 16, 2015 JCU press release (also on EurekAlert), which originated the news item, provides more detail,

“If you have seen how drops of water roll off a car after it is waxed, or off a couch that’s had protective spray used on it, you’ve seen the process happening,” she said. “The wax and spray make the surface very bumpy at micro and nano levels, and the water droplets remain as little balls, which roll easily and come off with gravity or even a slight wind.”

The geckos’ hair-like spines trap pockets of air and work on the same principle, but have an even more dramatic effect. Through a scanning electron microscope, tiny water droplets can be seen rolling into each other and jumping like popcorn off the skin of the animal as they merge and release energy.

Scientists were aware that hydrophobic surfaces repelled water, and that the rolling droplets helped clean the surfaces of leaves and insects, but this is the first time it has been documented in a vertebrate animal. Box-patterned geckos live in semi-arid habitats, with little rain but may have dew forming on them when the temperature drops overnight.

Professor Schwarzkopf said the process may help geckos keep clean, as the water can carry small particles of dust and dirt away from their body. “They tend to live in dry environments where they can’t depend on it raining, and this keeps process them clean,” she said.

She said there were possible applications for marine-based electronics that have to shed water quickly in use and for possible “superhydrophobic” clothing that would not get wet or dirty and would never need washing.

I’ve been reading about self-cleaning products for years now. (sigh) Where are they? Despite this momentary lapse into sighing and wailing, I am much encouraged that scientists are still trying to figure out how to create self-cleaning products.

Here’s a link to and a citation for the paper,

Removal mechanisms of dew via self-propulsion off the gecko skin by Gregory S. Watson, Lin Schwarzkopf, Bronwen W. Cribb, Sverre Myhra, Marty Gellender, and Jolanta A. Watson.
Interface, April 2015, Volume: 12 Issue: 105 DOI: 10.1098/rsif.2014.1396 Published 11 March 2015

This paper is open access.

*’2014′ corrected to ‘2015’ on Feb. 28, 2017.

Philippe Starck’s luggage goes nano

For anyone unfamiliar with Philippe Starck, there’s this from his Wikipedia entry (Note: Links have been removed),

Philippe Starck is a French designer[1] who has become widely known since the start of his career in the 1980s[2] for his interior, product, industrial and architectural design work.

A minimalist, Starck’s work is ‘stark’. In an interesting publicity campaign, his latest collection of travel gear is mentioned in a Feb. 4, 2015 news item on Nanotechnology Now,

In association with Philippe Starck, renowned French creator, designer and architect, DELSEY is reinventing the world of travel with the launch of STARCKTRIP, a new collection of luggage conceived on a single concept: intelligence in motion. Bold, original and innovative, leaving the fickle constraints of fashion behind to embrace timelessness.

The launch for this line was originally announced in an Oct. 9, 2014 Starck press release which includes a bit about the nanotechnology-enabled features of this luggage,

The materials used take advantage of the latest technological innovations but manage to be discrete about it. Nanotechnology is used to protect the bags and
cases, inside and out, from dirt and bacteria; fabric screens also protect against data theft; gentle plastic moulded material provides unparalleled rolling comfort, smoothness and silence. In addition, anti-rain treatment of the surfaces ensures that you, the business traveller, keep your belongings dry at all times. [emphases mine]

I’m not sure about the dirt but the protection from bacteria makes it sound like they’ve added nanoscale silver to the luggage and the anti-rain treatment sounds like a nanotechnology-enabled superhydrophobic coating of some kind. Unfortunately there are no details to be had on either Philippe Starck’s website or on the Delsey website. BTW, the middle-aged male model in the Starck press release, is M. Philippe Starck himself.

Do Tenebrionind beetles collect dew or condensation—a water issue at the nanoscale

Up until now, the research I’ve stumbled across about Tenebrionind beetles and their water-collecting ways has been from the US but this latest work comes from a France/Spain,/UK collaboration which focused on a specific question, exactly where do these beetles harvest their water from? A Dec. 8, 2014 news item on Nanotechnology Now describes this latest research,

Understanding how a desert beetle harvests water from dew could improve drinking water collection in dew condensers

Insects are full of marvels – and this is certainly the case with a beetle from the Tenebrionind family, found in the extreme conditions of the Namib desert. Now, a team of scientists has demonstrated that such insects can collect dew on their backs – and not just fog as previously thought. This is made possible by the wax nanostructure on the surface of the beetle’s elytra. … They bring us a step closer to harvesting dew to make drinking water from the humidity in the air. This, the team hopes, can be done by improving the water yield of man-made dew condensers that mimick the nanostructure on the beetle’s back.

A Dec. 8, 2014  Springer press release (also on EurekAlert), which originated the news item, describes how this research adds to the body of knowledge about the ability to harvest water from the air,

It was not clear from previous studies whether water harvested by such beetles came from dew droplets, in addition to fog. Whereas fog is made of ready-made microdroplets floating in the air, dew appears following the cooling of a substrate below air temperature. This then turns the humidity of air into tiny droplets of water because more energy – as can be measured through infrared emissions – is sent to the atmosphere than received by it. The cooling capability is ideal, they demonstrated, because the insect’s back demonstrates near-perfect infrared emissivity.

Guadarrama-Cetina [José Guadarrama-Cetina] and colleagues also performed an image analysis of dew drops forming on the insect’s back on the surface of the elytra, which appears as a series of bumps and valleys. Dew primarily forms in the valleys endowed with a hexagonal microstructure, they found, unlike the smooth surface of the bumps. This explains how drops can slide to the insect’s mouth when they reach a critical size.

Here’s a link to and a citation for the paper,

Dew condensation on desert beetle skin by J.M. Guadarrama-Cetina, A. Mongruel, M.-G. Medici, E. Baquero, A.R. Parker, I. Milimouk-Melnytchuk, W. González-Viñas, and D. Beysens. Eur. Phys. J. E (European Physics Journal E 2014) 37: 109, DOI 10.1140/epje/i2014-14109-y

This paper is currently (Dec. 8, 2014) open access. I do not know if this will be permanent or if access rights will change over time.

My previous postings on the topic of water and beetles have focused on US research of the Stenocara beetle (aka Namib desert beetle) which appears to be a member of the Tenebrionind family of beetles mentioned in this latest research.

The European researchers have provided an image of the beetle they were examining,

A preserved specimen of the Tenebrionind beetle (Physasterna cribripes) was used for this study, displaying the insect’s mechanisms of dew harvesting. © J.M. Guadarrama-Cetina et al.

A preserved specimen of the Tenebrionind beetle (Physasterna cribripes) was used for this study, displaying the insect’s mechanisms of dew harvesting. © J.M. Guadarrama-Cetina et al.

As for my other pieces on this topic, there’s a July 29, 2014 post, a June 18, 2014 post, and a Nov. 26, 2012 post.

Keeping your chef’s jackets clean and a prize for Teijin Aramid/Rice University

Australian start-up company, Fabricor Workwear launched a Kickstarter campaign on Sept. 18, 2014 to raise funds for a stain-proof and water-repellent chef’s jacket according to a Sept. 25, 2014 news item on Azonano,

An Australian startup is using a patented nanotechnology to create ‘hydrophobic’ chef jackets and aprons. Fabricor says this means uniforms that stay clean for longer, and saving time and money.

The company was started because cofounder and MasterChef mentor Adrian Li, was frustrated with keeping his chef jackets and aprons clean.

“As a chef I find it really difficult to keep my chef jacket white, and we like our jackets white,” Li said. …

The nanotechnology application works by modifying the fabric at a molecular level by permanently attaching hydrophobic ‘whiskers’ to individual fibres which elevate liquids, causing them to bead up and roll off.

The Fabricor: Stain-proof workwear for the hospitality industry Kickstarter campaign has this to say on its homepage (Note: Links have been removed),

Hi Kickstarters,

Thanks for taking the time check out our campaign.

Traditional chef jackets date back to the mid 19th century and since then haven’t changed much.

We’re tired of poor quality hospitality workwear that doesn’t last and hate spending our spare time and money washing or replacing our uniforms.

So we designed a range of stain-resistant Chef Jackets and Aprons using the world’s leading patented hydrophobic nanotechnology that repels water, dirt and oil.

Most stains either run off by themselves or can easily be rinsed off with a little water. This means they don’t need to be washed as often saving you time and money.

We’re really proud of what we’ve created and we hope you you’ll support us.

Adrian Li

Head Chef at Saigon Sally
Mentor on MasterChef Australia – Asian Street Food Challenge
Cofounder at Fabricor Workwear

At this point (Sept. 24, 2014), the campaign has raised approximately $2700US towards a $5000US goal and there are 22 days left to the campaign.

I did find more information at the Fabricor Workwear website in this Sept. 13, 2014 press release,

The fabric’s patented technology can extend the life of the apparel is because the apparel doesn’t have to be washed as often and can be washed in cooler temperatures, the company stated.

Fabricor’s products are not made with spray-application like many on the market which can destroy fabrics and contain carcinogenic chemical. Its hydrophobic properties are embedded into the weave during the production of the fabric.

Li said chefs spend too much money on chef jackets that are poorly designed and don’t last. The long-lasting fabric in Fabricor’s chef’s apparel retains its natural softness and breathability.

It seems to me that the claim about fewer washes can be made for all superhydrophobic textiles. As for carcinogenic chemicals in other superhydrophobic textiles, it’s the first I’ve heard of it, which may or may not be significant. I.e., I look at a lot of material but don’t focus on superhydrophobic textiles here and do not seek out research on risks specific to these textiles.

Teijin Aramid/Rice University

Still talking about textile fibres but on a completely different track, I received a news release this morning (Sept. 25, 2014) from Teijin Aramid about carbon nanotubes and fibres,

Researchers of Teijin Aramid, based in the Netherlands, and Rice University in the USA are awarded with the honorary ‘Paul Schlack Man-Made Fibers Prize’ for corporate-academic partnerships in fiber research. Their new super fibers are now driving innovation in aerospace, healthcare, automotive, and (smart) clothing.

The honorary Paul Schlack prize was granted by the European Man-made Fibers Association to Dr. Marcin Otto, Business Development Manager at Teijin Aramid and Prof. Dr. Matteo Pasquali from Rice University Texas, for the development of a new generation super fibers using carbon nanotubes (CNT). The new super fibers combine high thermal and electrical conductivity, as seen in metals, with the flexibility, robust handling and strength of textile fibers.

“The introduction of carbon nanotube fibers marked the beginning of a series of innovations in various industries”, says Marcin Otto, Business Development Manager at Teijin Aramid. “For example, CNT fibers can be lifesaving for heart patients: one string of CNT fiber in the cardiac muscle suffices to transmit vital electrical pulses to the heart. Or by replacing copper in data cables and light power cables by CNT fibers it’s possible to make satellites, aircraft and high end cars lighter and more robust at the same time.”

Since 1971, the Paul Schlack foundation annually grants one monetary prize to an individual young researcher for outstanding research in the field of fiber research, and an honorary prize to the leader(s) of excellent academic and corporate research partnerships to promote research at universities and research institutes.

For several years, leading researchers at Rice University and Teijin Aramid worked together on the development of CNT production. Teijin Aramid and Rice University published their research findings on carbon nanotubes fibers in the leading scientific journal, Science, beginning of 2013.

Teijin Aramid and some of its carbon nanotube projects have been mentioned here before, notably, in a Jan. 11, 2013 posting and in a Feb. 17, 2014.

Good luck on the Kickstarter campaign and congratulations on the award!

Nanex Canada (?) opens office in United States

Earlier this month in a Sept. 5, 2014 posting I noted that a Belgian company was opening a Canadian subsidiary in Montréal, Québec, called Nanex Canada. Not unexpectedly, the company has now announced a new office in the US. From a Sept. 23, 2014 Nanex Canada news release on Digital Journal,

Nanex Canada appoints Patrick Tuttle, of Havre de Grace, Maryland as the new USA National Sales Director. Tuttle will be in charge of all operations for the USA marketing and distribution for the Nanex Super hydrophobic Water Repellent Nanotechnology products.

… Nanex Canada is proud to announce a new partnership with Patrick Tuttle to develop the market within the Unites States for Its new line of super hydrophobic products. “We feel this is a very strategic alliance with Mr. Tuttle and his international marketing staff,” said Boyd Soussana, National Marketing Director for the parent company, Nanex Canada.

The products Mr. Tuttle will be responsible for in developing a market for include:

1) Aqua Shield Marine

2) Aqua Shield Leather and Textile

3) Aqua Shield Exterior: Wood, Masonry, Concrete

4) Aqua Shield Sport: Skiing, Snowboarding, Clothing

5) Aqua Shield Clear: Home Glass and Windshield Coating

6) Dryve Shield: For all Auto Cleaning and Shine

Soussana went on to say “the tests we have done in Canada on high dollar vehicles and the feedback from the Marine industry have been excellent. We are hearing from boat owners that they are seeing instant results in cleaning and protection from the Aqua Shield Marine products from the teak, to the rails and the fiberglass as well”

Boyd Soussana told me they did a private test on some very high end vehicles and the owners were very impressed, according to him.

So what is a Super hydrophobic Water Repellent Nanotechnology Product and how does it work?

A superhydrophobic coating is a nanoscopic surface layer that repels water and also can reduce dirt and friction against the surface to achieve better fuel economies for the auto and maritime industries according to Wikipedia.

About Nanex Company

Nanex is a developer of commercialized nanotechnology solutions headquartered in Belgium operating in North America through its Canadian subsidiary Nanex Canada Incorporated. At the start of 2012 it launched its first product, an advanced super hydrophobic formula called Always Dry. By 2014 Nanex had distributors around the world from Korea, Malaysia, and Singapore, to England and Eastern Europe, and had expanded its products into three lines and several formulas.

Given the remarkably short time span between opening a Canadian subsidiary and opening an office in the US, it’s safe to assume that obtaining a toehold in the US market was Nanex’s true objective.

Canadian nano business news: international subsidiary (Nanex) opens in Québec and NanoStruck’s latest results on recovering silver from mine tailings

The Canadian nano business sector is showing some signs of life. Following on my Sept. 3, 2014 posting about Nanotech Security Corp.’s plans to buy a subsidiary business, Fortress Optical Features, there’s an international subsidiary of Nanex (a Belgium-based business) planning to open in the province of Québec and NanoStruck (an Ontario-based company) has announced the results of its latest tests on cyanide-free recovery techniques.

In the order in which I stumbled across these items, I’m starting with the Nanex news item in a Sept. 3, 2014 posting on the Techvibes blog,

Nanex, a Belgian-based innovator and manufacturer of superhydrophobic nanotechnology products, announced last week the creation of its first international subsidiary.

Nanex Canada will be headquartered in Montreal.

For those unfamiliar with the term superhydrophobic, it means water repellent to a ‘super’ degree. For more information the properties of superhydrophobic coatings, the Techvibes post is hosting a video which demonstrates the coating’s properties (there’s a car which may never need washing again).

An Aug. 1, 2014 Nanex press release, which originated the news item, provides more details,

… Nanex Canada Incorporated will be starting operations on October 1st, 2014 and will be headquartered in Montreal, Quebec.

“Nanex’s expansion into Canada is a tremendous leap forward in our international operations, creating not only more efficient and direct channels into all of North America, but also providing access to a new top-notch intellectual pool for our R&D efforts,” Said Boyd Soussana, National Marketing Director at Nanex Canada. “We feel that Quebec and Canada have a great reputation as leaders in the field of advanced technologies, and we are proud to contribute to this scientific landscape.”

Upon launch, Nanex Canada Inc. will begin with retail and sales of its nanotechnology products, which have a wide range of consumer applications. Formal partnerships in B2B [business-to-business] further expanding these applications have been in place throughout Canada beginning in August of 2014. Through its Quebec laboratories Nanex Canada Inc. will also be pursuing R&D initiatives, in order to further develop safe and effective nano-polymers for consumer use, focusing entirely on ease of application and cost efficiency for the end consumer. In addition application of nano-coatings in green technologies will be a priority for North American R&D efforts.

Nanex Company currently manufactures three lines of products: Always Dry, Clean & Coat, and a self-cleaning coating for automotive bodies. These products contain proprietary nano-polymers that when sprayed upon a surface provide advanced abilities including super hydrophobic (extremely water-repellent), oleophobic (extremely oil repellent), and scratch resistance as well as self-cleaning properties.


The second piece of news is featured in a Sept. 5, 2014 news item on Azonano,

NanoStruck Technologies Inc. is pleased to announce positive results from test work carried out on silver mine tailings utilizing proprietary cyanide free recovery technologies that returned up to 87.6% of silver from samples grading 56 grams of silver per metric ton (g/t).

A Sept. 4, 2014 NanoStruck news release, which originated the news item, provides more details,

Three leach tests were conducted using the proprietary mixed acid leach process. Roasting was conducted on the sample for two of the leach tests, producing higher recoveries, although the un-roasted sample still produced a 71% recovery rate.

87.6% silver recoveries resulted from a 4 hour leach time at 95 degrees Celsius, with the standard feed grind size of D80 175 micron of roasted material.
84.3% recoveries resulted from a 4 hour leach at 95 degrees Celsius with the standard feed grind size of D80 175 micron with roasted material at a lower acid concentration.
71% recoveries resulted from a 4 hour leach at 95 degrees Celsius from received material, with the standard feed grind size of D80 175 micron with an altered acid mix concentration.

The average recovery for the roasted samples was 86% across the two leach tests performed using the proprietary process.

Bundeep Singh Rangar, Interim CEO and Chairman of the Board, said: “These results further underpin the effectiveness of our processing technology. With our patented process we are achieving excellent recoveries in not only silver tailings, but also gold tailings as well, both of which have vast global markets for us.”

The proprietary process combines a novel mixed acid leach with a solvent extraction stage, utilizing specific organic compounds. No cyanide is used in this environmentally friendly process. The flow sheet design is for a closed loop, sealed unit in which all chemicals are then recycled.

Previous test work undertaken on other gold mine tailings utilizing the proprietary process resulted in a maximum 96.1% recovery of gold. Previous test work undertaken on other silver tailings resulted in a maximum 86.4% recovery of silver.

The technical information contained in this news release has been verified and approved by Ernie Burga, a qualified person for the purpose of National Instrument 43-101, Standards of Disclosure for Mineral Projects, of the Canadian securities administrators.

Should you choose to read the news release in its entirety, you will find that no one is responsible for the information should anything turn out to be incorrect or just plain wrong but, like Nanotech Security Corp., (as I noted in my Sept. 4, 2014 posting), the company is very hopeful.

I have mentioned NanoStruck several times here:

March 14, 2014 posting

Feb. 19, 2014 posting

Feb. 10, 2014 posting

Dec. 27, 2013 posting