Tel Aviv University: Israeli Scientists Develop The Future Of Flexible Display Screens: Using DNA Nanotechnology

Israeli 0422 flexible-screen-811x497Imagine an electronic screen that looks and feels like paper that could connect to your smartphone. You can shift your longer readings and video viewing to this bendable screen, then roll it up and throw it in your bag when you arrive at your subway stop. This may sound like sci-fi, but Israeli researchers have actually found a way to develop such thin, flexible screens you can use on the go.

A new Tel Aviv University study suggests that a novel DNA nanotechnology could produce a structure that can be used to produce ultra-thin, flexible screens. The research team’s building blocks are three molecules they’ve synthesized, which later self-assembled into ordered structures. Essentially, the team has built the molecular backbone of a super-slim, bendable digital display. In the field of bio-nanotechnology, scientists utilize these molecular building blocks to develop cutting-edge technologies with properties not available for inorganic materials such as plastic and metal.


This could provide a solution to roughly 2 billion smartphone users who may not want the content they view to be confined to a pocket-sized screen. That’s because currently the size of smartphone screens makes it particularly hard to read more than a few hundred words at a time or watch videos without feeling like you’re on the tilt-a-whirl at Six Flags.

The number of people using mobile devices to view media is on the rise. According to Pew Research Center, 68 percent of smartphone owners use their phone occasionally to follow breaking news stories, and 33 percent do it frequently. Moreover, YouTube reports that 50 percent of its 4 billion video views per month are watched on a mobile device.

SEE ALSO: CES 2015: The Best Of Israeli Tech

The structures formed by the researchers were found to emit light in every color, as opposed to other fluorescent materials that shine only in one specific color. Moreover, light emission was observed in response to electric voltage — which makes this technology a perfect candidate for display screens.

The TAU researchers, who recently published their findings in the scientific journal Nature Nanotechnology, are currently building a prototype of the screen and are in talks with major consumer electronics companies regarding the technology, which they’ve patented. “Our material is light, organic and environmentally friendly,” TAU’s Prof. Ehud Gazit said in a statement. “It is flexible, and its single layer emits the same range of light that requires several layers today.” Moreover, fewer layers are better for consumers, he says: “By using only one layer, you can minimize production costs dramatically, which will lead to lower prices.”

lg g flex

Back to the good old newspaper display? 

It’s important to mention that this technology is still in its early stages and a price tag for these screens remains unknown. What is clear, however, is that the desire to consume content on portable, large screens isn’t going away and consumer preferences are trending more and more toward bigger screens.

Ironically, people seem to be drawn back to the old newspaper display – thin, flexible, and capable of being rolled up; now, all of these features are turning digital.

Regardless of flexibility, the tendency to enlarge mobile screens was already evident last year. It is widely believed that sales of Apple and Samsung (500 million smartphone in 2014) were buoyed by their newest smartphone iterations which boast larger screens than past versions. Apple especially took note of this trend, releasing the iPhone 6 (4.7 inch screen) and iPhone 6 Plus (5.5 inches) simultaneously.


Photos and video: LGU.S. Army RDECOM

Northwestern University: Counterfeit “Foilers” of All Kinds: Nano-Fluorescent Invisible Inks

Silicon Photonics id39403Real or counterfeit? Northwestern Univ. scientists have invented sophisticated fluorescent inks that one day could be used as multicolored barcodes for consumers to authenticate products that are often counterfeited. Snap a photo with your smartphone, and it will tell you if the item is real and worth your money.

Counterfeiting is very big business worldwide, with $650 billion per year lost globally, according to the International Chamber of Commerce. The new fluorescent inks give manufacturers and consumers an authentication tool that would be very difficult for counterfeiters to mimic.

These inks, which can be printed using an inkjet printer, are invisible under normal light but visible under ultraviolet light. The inks could be stamped as barcodes or QR codes on anything from banknotes and bottles of whisky to luxury handbags and expensive cosmetics, providing proof of authenticity.

A key advantage is the control one has over the color of the ink; the inks can be made in single colors or as multicolor gradients. An ink’s color depends on the amounts and interaction of three different “ingredient” molecules, providing a built-in “molecular encryption” tool. (One of the ingredients is a sugar.) Even a tiny tweak to the ink’s composition results in a significant color change.

“We have introduced a level of complexity not seen before in tools to combat counterfeiters,” said Sir Fraser Stoddart, the senior author of the study. “Our inks are similar to the proprietary formulations of soft drinks. One could approximate their flavor using other ingredients, but it would be impossible to match the flavor exactly without a precise knowledge of the recipe.”

Sir Fraser is the Board of Trustees Professor of Chemistry in the Weinberg College of Arts and Sciences.

“The rather unusual relationship between the composition of the inks and their color makes them ideal for security applications where it’s desirable to keep certain information encrypted or to have brand items with unique labels that can be authenticated easily,” Stoddart said.

With a manufacturer controlling the ink’s “recipe,” or chemical composition, counterfeiters would find it virtually impossible to reverse engineer the color information encoded in the printed barcodes, QR codes or trademarks. Even the inks’ inventors would not be able to reverse engineer the process without a detailed knowledge of the encryption settings.

Details of the fluorescent inks, which are prepared from simple and inexpensive commodity chemicals, are published in Nature Communications.

Stoddart’s research team, led by Xisen Hou and Chenfeng Ke, stumbled across the water-based ink composite serendipitously. A series of rigorous follow-up investigations unraveled the mechanism of the unique behavior of the inks and led the scientists to propose an encryption theory for security printing.

Hou, a third-year graduate student, and Ke, a postdoctoral fellow, are co-first authors of the paper.

The researchers developed an encryption and authentication security system combined with inkjet-printing technology. In the study, they demonstrated both a monochromic barcode and QR code printed on paper from an inkjet printer. The information, invisible under natural light, can be read on a smartphone under UV light.

As another demonstration of the technology, the research team loaded the three chemical components into an inkjet cartridge and printed Vincent Van Gogh’s “Sunflowers” painting with good color resolution. Like the barcodes and QR codes, the printed image is only visible under UV light.

The inks are formulated by mixing a simple sugar (cyclodextrin) and a competitive binding agent together with an active ingredient (a molecule known as heterorotaxane) whose fluorescent color changes along a spectrum of red to yellow to green, depending upon the way the components come together. An infinite number of combinations can be defined easily.

Although the sugar itself is colorless, it interacts with the other components of the ink, encapsulating some parts selectively, thus preventing the molecules from sticking to one another and causing a change in color that is difficult to predict. This characteristic presents a formidable challenge to counterfeiters.

Hou and Ke were trying to prevent fluorophore aggregation by encircling a fluorescent molecule with other ring-shaped molecules, one being cyclodextrin. Unexpectedly, they isolated the compound that is the active ingredient of the inks. They found that the compound’s unusual arrangement of three rings trapped around the fluorescent component affords the unique aggregation behavior that is behind the color-changing inks.

“You never know what Mother Nature will give you,” Hou said. “It was a real surprise when we first isolated the main component of the inks as an unexpected byproduct. The compound shows a beautiful dark-red fluorescence under UV light, yet when we dissolve it in large amounts of water, the fluorescent color turns green. At that moment, we realized we had discovered something that is quite unique.”

The fluorescent colors can be tuned easily by adding the sugar dissolved in water. As more cyclodextrin is added, the fluorescent color changes from red to yellow and then green, giving a wide range of beautiful colors. The fluorescent color can be reversed, by adding another compound that mops up the cyclodextrin.

The researchers also discovered that the fluorescent ink is sensitive to the surface to which it is applied. For example, an ink blend that appears as orange on standard copy paper appears as green on newsprint. This observation means that this type of fluorescent ink can be used to identify different papers.

“This is a smart technology that allows people to create their own security code by manually setting all the critical parameters,” Hou said. “One can imagine that it would be virtually impossible for someone to reproduce the information unless they knew exactly all the parameters.”

The researchers also have developed an authentication mechanism to verify the protected information produced by the fluorescent security inks. Simply by wiping some wet authentication wipes on top of the fluorescent image causes its colors to change under UV light.

“Since the color changing process is dynamic, even if counterfeiters can mimic the initial fluorescent color, they will find it impossible to reproduce the color-changing process,” Ke emphasized.

Source: Northwestern Univ.

Parkinson’s-like Symptoms Reversed in Lab Rats by Nanoparticle Drug

Parkinsons Lab Rat 0422 nanoparticle As baby boomers age, the number of people diagnosed with Parkinson’s disease is expected to increase. Patients who develop this disease usually start experiencing symptoms around age 60 or older. Currently, there’s no cure, but scientists are reporting a novel approach that reversed Parkinson’s-like symptoms in rats. Their results, published in the journal ACS Nano, could one day lead to a new therapy for human patients.

Rajnish Kumar Chaturvedi, Kavita Seth, Kailash Chand Gupta and colleagues from the CSIR-Indian Institute of Toxicology Research note that among other issues, people with Parkinson’s lack in the brain. Dopamine is a chemical messenger that helps nerve cells communicate with each other and is involved in normal body movements. Reduced levels cause the shaking and mobility problems associated with Parkinson’s. Symptoms can be relieved in animal models of the disease by infusing the compound into their brains. But researchers haven’t yet figured out how to safely deliver dopamine directly to the human brain, which is protected by something called the that keeps out pathogens, as well as many medicines. Chaturvedi and Gupta’s team wanted to find a way to overcome this challenge.


Parkinsons Lab Rat 0422 nanoparticle

The researchers packaged dopamine in biodegradable nanoparticles that have been used to deliver other therapeutic drugs to the brain. The resulting nanoparticles successfully crossed the blood-brain barrier in rats, released its dopamine payload over several days and reversed the rodents’ movement problems without causing side effects.

Explore further: Hunting down the trigger for Parkinson’s: Failing dopamine pump damages brain cells

More information: Trans-Blood Brain Barrier Delivery of Dopamine Loaded Nanoparticles Reverses Functional Deficits in Parkinsonian Rats, ACS Nano, Article ASAP, DOI: 10.1021/nn506408v

Sustained and safe delivery of dopamine across the blood brain barrier (BBB) is a major hurdle for successful therapy in Parkinson’s disease (PD), a neurodegenerative disorder. Therefore, in the present study we designed neurotransmitter dopamine-loaded PLGA nanoparticles (DA NPs) to deliver dopamine to the brain. These nanoparticles slowly and constantly released dopamine, showed reduced clearance of dopamine in plasma, reduced quinone adduct formation, and decreased dopamine autoxidation. DA NPs were internalized in dopaminergic SH-SY5Y cells and dopaminergic neurons in the substantia nigra and striatum, regions affected in PD. Treatment with DA NPs did not cause reduction in cell viability and morphological deterioration in SH-SY5Y, as compared to bulk dopamine-treated cells, which showed reduced viability. Herein, we report that these NPs were able to cross the BBB and capillary endothelium in the striatum and substantia nigra in a 6-hydroxydopamine (6-OHDA)-induced rat model of PD. Systemic intravenous administration of DA NPs caused significantly increased levels of dopamine and its metabolites and reduced dopamine-D2 receptor supersensitivity in the striatum of parkinsonian rats. Further, DA NPs significantly recovered neurobehavioral abnormalities in 6-OHDA-induced parkinsonian rats. Dopamine delivered through NPs did not cause additional generation of ROS, dopaminergic neuron degeneration, and ultrastructural changes in the striatum and substantia nigra as compared to 6-OHDA-lesioned rats. Interestingly, dopamine delivery through nanoformulation neither caused alterations in the heart rate and blood pressure nor showed any abrupt pathological change in the brain and other peripheral organs. These results suggest that NPs delivered dopamine into the brain, reduced dopamine autoxidation-mediated toxicity, and ultimately reversed neurochemical and neurobehavioral deficits in parkinsonian rats.


South Korea to Develop and Commercialize Graphene by 2017: Become World Leader: Market Value of $17.46 Billion

Korea Graphene 0422 AP322310671385-1024x576SEJONG, April 6 (Yonhap) — South Korea will move to start producing and selling products using graphene by as early as 2017, becoming one of the world’s first countries to commercialize the new advanced material, the government said Monday.

Graphene is an atom-thin sheet of carbon that can transmit electric currents by up to 1 million times faster than conventional conductors, such as copper, and has twice the strength of diamonds. The material can be used in various applications, including flexible display panels and touch-screen panels.

South Korea’s aim to become one of the world’s first nations to commercialize the new material began a decade earlier while the government named six consortia made up of 45 private firms and research institutes in 2013 to develop related technologies.

Korea Graphene 0422 AP322310671385-1024x576

Graphene IC in wafer tester (AP/PRNewsFoto/IBM)

“The country believes it can create a new global market for graphene under its leadership as the country has developed leading technologies through over 10 years of research while it also has enough demand for the material in the mobile phone, display and secondary cell battery sectors,” the Ministry of Trade, Industry and Energy said in a press release.

Under the latest plan, unveiled and endorsed at a meeting of the National Science and Technology Council, the government will continue to support research and development of related technologies that will enable mass production of the material by 2020.

“We expect to secure 85 key technologies related to graphene by 2020 through cooperation between the public and private sectors under the new plan,” the ministry said, noting it expects to see the first commercial product, an electromagnetic shield, in 2017.

The new technologies and products will help create some 52,000 new jobs while generating over 19 trillion won (US$17.46 billion) in sales in 2025, it added.

Oakridge National Laboratory: Using New Graphene Technology to Desalinate Water

Given that less than 1 percent of the water on the planet is drinkable, a process to remove minerals, like salt, from water could help to alleviate many problems for the global community.
In the U.S., a research group based at the Department of Energy’s Oak Ridge National Laboratory have been working on a low-energy efficient desalination process. The newly devised method deploys a porous membrane made of graphene.

Graphene is a very strong, low weight material. It is 100 times stronger than steel and it conducts heat and electricity with great efficiency. The material is being investigated for many potential applications, including water purification.

The graphene membrane is, according to the researchers, more effective and uses less energy compared with current polymeric membranes, which work on the basis of reverse osmosis. With reverse osmosis an applied pressure is used to overcome osmotic pressure; this allows water to pass through a membrane whilst at the same time particles are retained.

With the new method the most important aspect is making the pores in the graphene. The size here is important: large enough to allow water molecules to pass through but sufficiently small to stop salt molecules from traversing the mesh.

The reason that the graphene process is more energy efficient comes down to the size of the mesh. Graphene is considerably thinner (just one atom in thickness) than the plastic polymers and the result of this is that less energy is required to push the fluid through.

The graphene structure was manufactured by passing methane gas through a tube furnace at 1,000 degrees C over a copper foil. This decomposed the methane into carbon and hydrogen. The carbon then assembled into a hexagonal configuration of one atom thick molecules. The graphene was then mounted onto a silicon nitride support. Small pores in the graphene are created using a plasma (an ionized gas.) Pores were created at the rate of one pore for every 100 square nanometers of graphene.

In experimental runs the graphene filter was used to remove salt from sea water in order to create water of drinking water quality. The test runs were effective with almost 100 percent of the salt removed.

The research has been published in the journal Nature Nanotechnology. The title of the paper is “Water Desalination Using Nanoporous Single-Layer Graphene.”

Read more:

Using Nanotechnology to Build a Space Elevator: (With Video) Not So Crazy of an Idea:

Space Elevator 0422 ImageForArticle_4011(1)A space elevator may sound like an idea that could only exist in science fiction but we may be closer to seeing one in the near future than you might have previously thought. By William Wassmer

2050: A Space Odyssey

A Japanese company, called Obayashi Corporation, recently announced that it intends to build a fully working space elevator by the year 2050. This space elevator would drastically reduce the risks and costs associated with space travel in the future. A space elevator would act as a direct transport route to the frontier of space.

Diamond Nanothreads

The space elevator still has a lot of theoretical challenges to overcome before it can be realised. Currently the largest challenge facing the space elevator project is the creation of a cable that would be strong enough to support the immense forces that it would be subjected to.

Advances in research into nanotechnology and carbon nanotube materials are now presenting us with the opportunity to create a cable that could actually handle the forces that would be exerted on it.

Researchers are currently exploring the idea of using ‘diamond nano-threads’ as the material of choice for a space elevator cable. These nanothreads, which are currently being developed by John V. Badding and his research team at Penn State University, have a unique structure compared to other carbon nanotubes.

John Badding, Professor of Chemistry at Penn State, Talks About his Research

The unique structure which diamond nanothreads have is achieved by compressing benzene, a ring of six carbon atoms, causing the benzene to stack. Eventually the pressure becomes too much and the benzene breaks apart, only to reform again in the shape of a tetrahedron as the pressure is slowly released by the scientists.

One of our wildest dreams for the nanomaterials we are developing is that they could be used to make the super-strong, lightweight cables that would make possible the construction of a space elevator which so far has existed only as a science-fiction idea.

John V. Badding, Professor of Chemistry at Penn State University

Badding’s team are the first to develop a structure in which tetrahedrons, pyramids with a triangular base, are connected end by end in order to form an incredibly strong structure.

Creating Incredibly Light and Incredibly Strong Cables

The strength of a diamond nanothread means that this nanomaterial could be used to create the cables of a space elevator. The cables need to be both incredibly light and incredibly strong in order to provide the stability required for a space elevator to operate.

Diamond nanothreads would be ideal for this use due to their stiffness and strength, as well as the fact that they are light in weight. However, currently used processes and techniques to create carbon nanotubes have limitations and are not yet able to produce the quantity or quality of nanomaterials which a space elevator cable would require.

However, the Obayashi Corporation believes that large scale production technology will have been established by 2030, leading them to predict that they could complete their space elevator project by 2050. The construction of a cable is the first step in creating a space elevator because it requires the most research in order to be fully realised.

Diamond Nanothreads – Image Credit: John Badding Lab | Penn State University

The Main Components of a Space Elevator

The other four main components required to build a space elevator are:

  • an anchoring station placed on the surface of the earth
  • a counterweight in space which will help stabilise the orbit of the cable
  • a mechanical lifter to pull the elevator up the cable
  • a power source located on the earth to deliver power to the elevator

The Anchoring Station

The anchoring station will serve as a starting base for space elevator missions and will most likely originate from a location in the Pacific Ocean. Using a location on the surface of the Pacific Ocean would allow the anchoring station to move along the ocean surface to help the cable avoid any threatening objects. A location along the equator in the Pacific Ocean would also help to minimise the threat that extreme weather could pose to the space elevator and its operation.

The Counterweight

The counterweight helps to stabilise the space elevator by keeping the cable at its maximum length and tension as it orbits around the earth. Researchers believe that the ideal counterweight could be the same spacecraft which will be used to launch the cable into space. This dual purpose spacecraft/counterweight would help to minimise the economic costs of the counterweight and the spacecraft delivering the cable.

An Elevator to Space: Markus Landgraf at TEDxRheinMain

The Mechanical Lifter

The mechanical lifter will work in conjunction with the cable to provide the elevator with its vertical motion. One of the potential designs for the lifter is a series of rollers with traction tread that would look something similar to the rollers on a tank. These rollers would pull the cable through the space elevator and thus pull the elevator upwards into space.

The Power Source

The power source will wirelessly deliver power from the anchoring station to the space elevator as it makes its journey upwards towards space. This can be done by firing a laser at photovoltaic cells, which will convert the energy from the laser into electricity that the mechanical lifter can use.

Whilst the concept of wirelessly transferred power sounds like something straight from the pages of a science fiction novel, we have been using microwaves to fly model aircraft for over 20 years.

Some Challenges to Overcome

Even if all of these components work in unison there are still a number of challenges that need to be overcome in order to create a working space elevator. For example, low earth orbit objects could potentially damage or cut the cable that the space elevator is using. If the cable was to be cut it could fall back to the earth and cause enormous damage to the anchor station and the surrounding area.

Another major concern which has to be considered is the political impact of creating a space elevator. If the space elevator’s anchor station is situated in international waters, then who would own the space elevator and how would you equally share the usage of the space elevator? These are just a few of the issues which have to be resolved before the space elevator becomes a reality.

Why is it Worth the Effort?

The current cost of transporting cargo into space using spacecraft is around $20,000 per kilogram. Using a space elevator, Obayashi claims that this cost will be drastically reduced to just of only a few hundred dollars per kilogram of cargo. Apart from the obvious benefits of transporting material into space in a more cost effective manner, a space elevator also has huge applications for space launches.

Overcoming the Earth’s gravitational field and atmosphere is one of the major costs and difficulties associated with a space shuttle launch. However, if a space elevator could transport a spacecraft into space ready to be launched, then the effects of gravity and atmosphere would no longer pose a challenge to space travel in the future.

The development of a space elevator represents an important first step towards travel and exploration into deep space, as well as opening up the possibility of a civilisation that spans our solar system.

References and Further Reading

UC San Diego: Increasing Energy Storage Capacity: Charged “Holes” in Graphene: Applications: Cars, Wind Turbines, Solar Power

UC San Diego 0422 chargedholesEngineers at the University of California, San Diego have discovered a method to increase the amount of electric charge that can be stored in graphene, a two-dimensional form of carbon. The research, published recently online in the journal Nano Letters, may provide a better understanding of how to improve the energy storage ability of capacitors for potential applications in cars, wind turbines, and solar power.

Capacitors charge and discharge very fast, and are more useful for quick large bursts of energy, such as in camera flashes and power plants. Their ability to rapidly charge and discharge is an advantage over the long charge time of batteries. However, the problem with capacitors is that they store less energy than batteries.

How can the of a capacitor be improved? One approach by researchers in the lab of mechanical engineering professor Prabhakar Bandaru at the Jacobs School of Engineering at UC San Diego was to introduce more charge into a capacitor electrode using graphene as a model material for their tests. The principle is that increased charge leads to increased capacitance, which translates to increased energy storage.

How it’s made

Making a perfect carbon nanotube structure ― one without , which are holes corresponding to missing ― is next to impossible. Rather than avoiding defects, the researchers in Bandaru’s lab figured out a practical way to use them instead.

“I was motivated from the point of view that charged defects may be useful for energy storage,” said Bandaru.

The team used a method called argon-ion based plasma processing, in which graphene samples are bombarded with positively-charged argon ions. During this process, carbon atoms are knocked out of the graphene layers and leave behind holes containing positive charges ― these are the charged defects. Exposing the graphene samples to argon plasma increased the capacitance of the materials three-fold.

Charged holes in graphene increase energy storage capacity
Zigzag and armchair defects in grahene

“It was exciting to show that we can introduce extra capacitance by introducing charged defects, and that we could control what kind of charged defect we could introduce into a material,” said Rajaram Narayanan, a graduate student in professor Bandaru’s research group and first author of the study.

Using Raman spectroscopy and electrochemical measurements, the team was able to characterize the types of defects that argon plasma processing introduced into the lattices. The results revealed the formation of extended defects known as “armchair” and “zigzag” defects, which are named based on the configurations of the missing carbon atoms.

Additionally, electrochemical studies helped the team discover a new length scale that measures the distance between charges. “This new length scale will be important for electrical applications, since it can provide a basis for how small we can make electrical devices,” said Bandaru.

Explore further: The chemical battle inside instantaneous energy storage devices

More information: “Modulation of the Electrostatic and Quantum Capacitances of Few Layered Graphenes through Plasma Processing.” Nano Letters 2015. DOI: 10.1021/acs.nanolett.5b00055

Technion Institute of Technology: Israeli Lung Cancer Detection Device Shown To Be Effective in Diagnosing Stomach Cancer

Israeli dna-694798_1280The NaNose technology, first used in detecting lung cancer, has now been shown as an effective tool in detecting early-stage gastric (stomach) cancer as well.

According to a study in the medical journal, Gut, the diagnostic tool developed by Dr. Hossam Haick of the Technion Institute of Technology matched the results picked up by the standard method of gastric cancer detection, called gas chromatography mass spectrometry (GCMS).

“The attraction of this test lies in its non-invasiveness, ease of use, rapid predictiveness, and potentially low cost,” said Prof Hossam Haick, of the Department of Chemical Engineering and Russell Berrie Nanotechnology Institute in Haifa.

The study showed that people with cancer and those without the disease had distinctive “breath prints.” The report said the test was also able to distinguish between the different pre-cancerous stages.

“Currently, there is no perfect noninvasive tool to screen for stomach cancer,” said Haick. “Small and inexpensive sensing technology could be developed and used to fulfill these clinical needs.”

An Israeli-led international consortium is seeking to commercialize the Na-Nose technology by integrating it into cell phones. Haick’s technology for detecting diseases by their scents has received funding from both the British and Israeli governments.

(via Israel21c)

[Photo: technion / YouTube ]

Ohio State: Nano-Mesh Could Clean Oil Spills for Less than $1 per square Foot

Oil Spills Ohio State 150415090028-largeThe unassuming piece of stainless steel mesh in a lab at The Ohio State University doesn’t look like a very big deal, but it could make a big difference for future environmental cleanups.

In tests, researchers mixed water with oil and poured the mixture onto the mesh. The water filtered through the mesh to land in a beaker below. The oil collected on top of the mesh, and rolled off easily into a separate beaker when the mesh was tilted.

The mesh coating is among a suite of nature-inspired nanotechnologies under development at Ohio State and described in two papers in the journal Nature Scientific Reports. Potential applications range from cleaning oil spills to tracking oil deposits underground.

“If you scale this up, you could potentially catch an oil spill with a net,” said Bharat Bhushan, Ohio Eminent Scholar and Howard D. Winbigler Professor of mechanical engineering at Ohio State.

Oil Spills Ohio State 150415090028-large

This mesh captures oil (red) while water (blue) passes through.
Credit: Photo by Jo McCulty, courtesy of The Ohio State University

The work was partly inspired by lotus leaves, whose bumpy surfaces naturally repel water but not oil. To create a coating that did the opposite, Bhushan and postdoctoral researcher Philip Brown chose to cover a bumpy surface with a polymer embedded with molecules of surfactant — the stuff that gives cleaning power to soap and detergent.

They sprayed a fine dusting of silica nanoparticles onto the stainless steel mesh to create a randomly bumpy surface and layered the polymer and surfactant on top.

The silica, surfactant, polymer, and stainless steel are all non-toxic and relatively inexpensive, said Brown. He estimated that a larger mesh net could be created for less than a dollar per square foot.

Because the coating is only a few hundred nanometers (billionths of a meter) thick, it is mostly undetectable. To the touch, the coated mesh doesn’t feel any bumpier than uncoated mesh. The coated mesh is a little less shiny, though, because the coating is only 70 percent transparent.

The researchers chose silica in part because it is an ingredient in glass, and they wanted to explore this technology’s potential for creating smudge-free glass coatings. At 70 percent transparency, the coating could work for certain automotive glass applications, such as mirrors, but not most windows or smartphone surfaces.

“Our goal is to reach a transparency in the 90-percent range,” Bhushan said. “In all our coatings, different combinations of ingredients in the layers yield different properties. The trick is to select the right layers.”

He explained that certain combinations of layers yield nanoparticles that bind to oil instead of repelling it. Such particles could be used to detect oil underground or aid removal in the case of oil spills.

The shape of the nanostructures plays a role, as well. In another project, research assistant Dave Maharaj is investigating what happens when a surface is made of nanotubes. Rather than silica, he experiments with molybdenum disulfide nanotubes, which mix well with oil. The nanotubes are approximately a thousand times smaller than a human hair.

Maharaj measured the friction on the surface of the nanotubes, and compressed them to test how they would hold up under pressure.

“There are natural defects in the structure of the nanotubes,” he said. “And under high loads, the defects cause the layers of the tubes to peel apart and create a slippery surface, which greatly reduces friction.”

Bhushan envisions that the molybdenum compound’s compatibility with oil, coupled with its ability to reduce friction, would make it a good additive for liquid lubricants. In addition, for micro- and nanoscale devices, commercial oils may be too sticky to allow for their efficient operation. Here, he suspects that the molybdenum nanotubes alone could be used to reduce friction.

This work began more than 10 years ago, when Bhushan began building and patenting nano-structured coatings that mimic the texture of the lotus leaf. From there, he and his team have worked to amplify the effect and tailor it for different situations.

“We’ve studied so many natural surfaces, from leaves to butterfly wings and shark skin, to understand how nature solves certain problems,” Bhushan said. “Now we want to go beyond what nature does, in order to solve new problems.”

“Nature reaches a limit of what it can do,” agreed Brown. “To repel synthetic materials like oils, we need to bring in another level of chemistry that nature doesn’t have access to.”

This work was partly funded by the American Chemical Society Petroleum Research Fund, the National Science Foundation, and Dexerials Corporation (formerly a chemical division of Sony Corp.) in Japan.

Story Source:

The above story is based on materials provided by Ohio State University.