MIT: New ‘Solar Skin’ Solar panels get a face-lift with custom Display Capabilities


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Startup aims for wider U.S. solar adoption with photovoltaic panels that can display any image.

Founded at the MIT Sloan School of Management, Sistine Solar creates custom solar panels designed to mimic home facades and other environments, as well as display custom designs, with aims of enticing more homeowners to install photovoltaic systems. Courtesy of Sistine Solar

Residential solar power is on a sharp rise in the United States as photovoltaic systems become cheaper and more powerful for homeowners. A 2012 study by the U.S. Department of Energy (DOE) predicts that solar could reach 1 million to 3.8 million homes by 2020, a big leap from just 30,000 homes in 2006.

But that adoption rate could still use a boost, according to MIT spinout Sistine Solar. “If you look at the landscape today, less than 1 percent of U.S. households have gone solar, so it’s nowhere near mass adoption,” says co-founder Senthil Balasubramanian MBA ’13.

Founded at the MIT Sloan School of Management, Sistine creates custom solar panels designed to mimic home facades and other environments, with aims of enticing more homeowners to install photovoltaic systems.

Sistine’s novel technology, SolarSkin, is a layer that can be imprinted with any image and embedded into a solar panel without interfering with the panel’s efficacy. Homeowners can match their rooftop or a grassy lawn. Panels can also be fitted with business logos, advertisements, or even a country’s flag. SolarSkin systems cost about 10 percent more than traditional panel installations. But over the life of the system, a homeowner can still expect to save more than $30,000, according to the startup.

A winner of a 2013 MIT Clean Energy Prize, Sistine has recently garnered significant media attention as a rising “aesthetic solar” startup. Last summer, one of its pilot projects was featured on the Lifetime television series “Designing Spaces,” where the panels blended in with the shingle roof of a log cabin in Hubbardston, Massachusetts.

In December, the startup installed its first residential SolarSkin panels, in a 10-kilowatt system that matches a cedar pattern on a house in Norwell, Massachusetts. Now, the Cambridge-based startup says it has 200 homes seeking installations, primarily in Massachusetts and California, where solar is in high demand.

“We think SolarSkin is going to catch on like wildfire,” Balasubramanian says. “There is a tremendous desire by homeowners to cut utility bills, and solar is finding reception with them — and homeowners care a lot about aesthetics.”

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Captivating people with solar – Who Said Solar Can’t Be Beautiful?

SolarSkin is the product of the co-founders’ unique vision, combined with MIT talent that helped make the product a reality.

Balasubramanian came to MIT Sloan in 2011, after several years in the solar-power industry, with hopes of starting his own solar-power startup — a passion shared by classmate and Sistine co-founder Ido Salama MBA ’13.

One day, the two were brainstorming at the Muddy Charles Pub, when a surprisingly overlooked issue popped up: Homeowners, they heard, don’t really like the look of solar panels. That began a nebulous business mission to “captivate people’s imaginations and connect people on an emotional level with solar,” Balasubramanian says.

Recruiting Jonathan Mailoa, then a PhD student in MIT’s Photovoltaic Research Laboratory, and Samantha Holmes, a mosaic artist trained in Italy who is still with the startup, the four designed solar panels that could be embedded on massive sculptures and other 3-D objects. They took the idea to 15.366 (Energy Ventures), where “it was drilled into our heads that you have to do a lot of market testing before you build a product,” Balasubramanian says.

That was a good thing, too, he adds, because they realized their product wasn’t scalable. “We didn’t want to make a few installations that people talk about. … We [wanted to] make solar so prevalent that within our lifetime we can see the entire world convert to 100 percent clean energy,” Balasubramanian says.

The team’s focus then shifted to manufacturing solar panels that could match building facades or street fixtures such as bus shelters and information kiosks. In 2013, the idea earned the team — then officially Sistine Solar — a modest DOE grant and a $20,000 prize from the MIT Clean Energy Prize competition, “which was a game-changer for us,” Balasubramanian says.

But, while trying to construct custom-designed panels, another idea struck: Why not just make a layer to embed into existing solar panels? Recruiting MIT mechanical engineering student Jody Fu, Sistine created the first SolarSkin prototype in 2015, leading to pilot projects for Microsoft, Starwood Hotels, and other companies in the region.

That summer, after earning another DOE grant for $1 million, Sistine recruited Anthony Occidentale, an MIT mechanical engineering student who has since helped further advance SolarSkin. “We benefited from the incredible talent at MIT,” Balasubramanian says. “Anthony is a shining example of someone who resonates with our vision and has all the tools to make this a reality.”

Imagination is the limit

SolarSkin is a layer that employs selective light filtration to display an image while still transmitting light to the underlying solar cells. The ad wraps displayed on bus windows offer a good analogy: The wraps reflect some light to display an image, while allowing the remaining light through so passengers inside the bus can see out. SolarSkin achieves a similar effect — “but the innovation lies in using a minute amount of light to reflect an image [and preserve] a high-efficiency solar module,” Balasubramanian says.

To achieve this, Occidentale and others at Sistine have developed undisclosed innovations in color science and human visual perception. “We’ve come up with a process where we color-correct the minimal information we have of the image on the panels to make that image appear, to the human eye, to be similar to the surrounding backdrop of roof shingles,” Occidentale says.

As for designs, Sistine has amassed a database of common rooftop patterns in the United States, such as asphalt shingles, clay tiles, and slate, in a wide variety of colors. “So if a homeowner says, for instance, ‘We have manufactured shingles in a barkwood pattern,’ we have a matching design for that,” he says. Custom designs aren’t as popular, but test projects include commercial prints for major companies, and even Occidentale’s face on a panel.

Currently, Sistine is testing SolarSkin for efficiency, durability, and longevity at the U.S. National Renewable Energy Laboratory under a DOE grant.

The field of aesthetic solar is still nascent, but it’s growing, with major companies such as Tesla designing entire solar-panel roofs. But, as far as Balasubramanian knows, Sistine is the only company that’s made a layer that can be integrated into any solar panel, and that can display any color as well as intricate patterns and actual images.

Companies could thus use SolarSkin solar panels to double as business signs. Municipalities could install light-powering solar panels on highways that blend in with the surrounding nature. Panels with changeable advertisements could be placed on bus shelters to charge cell phones, information kiosks, and other devices. “You can start putting solar in places you typically didn’t think of before,” Balasubramanian says. “Imagination is really the only limit with this technology.”

Oregon St. University: New hydronium-ion battery show promise for sustainable energy storage


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February 20, 2017

 
A new type of battery developed by scientists at Oregon State University shows promise for sustainable, high-power energy storage.

It’s the world’s first battery to use only hydronium ions as the charge carrier.
The new battery provides an additional option for researchers, particularly in the area of stationary storage.

 
Stationary storage refers to batteries in a permanent location that store grid power – including power generated from alternative energy sources such as wind turbines or solar cells – for use on a standby or emergency basis.

 
Hydronium, also known as H3O+, is a positively charged ion produced when a proton is added to a water molecule. Researchers in the OSU College of Science have demonstrated that hydronium ions can be reversibly stored in an electrode material consisting of perylenetetracarboxylic dianhydridem, or PTCDA.

 
This material is an organic, crystalline, molecular solid. The battery, created in the Department of Chemistry at Oregon State, uses dilute sulfuric acid as the electrolyte.
Graduate student Xingfeng Wang was the first author on the study, which has been published in the journal Angewandte Chemie International Edition, a publication of the German Chemical Society.

 
“This may provide a paradigm-shifting opportunity for more sustainable batteries,” said Xiulei Ji, assistant professor of chemistry at OSU and the corresponding author on the research. “It doesn’t use lithium or sodium or potassium to carry the charge, and just uses acid as the electrolyte. There’s a huge natural abundance of acid so it’s highly renewable and sustainable.” Ji points out that until now, cations – ions with a positive charge – that have been used in batteries have been alkali metal, alkaline earth metals or aluminum.
“No nonmetal cations were being considered seriously for batteries,” he said.
The study observed a big dilation of the PTCDA lattice structure during intercalation – the process of its receiving ions between the layers of its structure. That meant the electrode was being charged, and the PTCDA structure expanded, by hydronium ions, rather than extremely tiny protons, which are already used in some batteries.

 
“Organic solids are not typically contemplated as crystalline electrode materials, but many are very crystalline, arranged in a very ordered structure,” Ji said. “This PTCDA material has a lot of internal space between its molecule constituents so it provides an opportunity for storing big ions and good capacity.” The hydronium ions also migrate through the electrode structure with comparatively low “friction,” which translates to high power.
“It’s not going to power electric cars,” Ji said. “But it does provide an opportunity for battery researchers to go in a new direction as they look for new alternatives for energy storage, particularly for stationary grid storage.”

More information: Xingfeng Wang et al, Hydronium-Ion Batteries with Perylenetetracarboxylic Dianhydride Crystals as an Electrode, Angewandte Chemie International Edition (2017). DOI: 10.1002/anie.201700148
Provided by: Oregon State University

MIT.nano ~ Inspiring Innovation at the ‘nano-scale’ … Making Our World Better – One Atom at a Time: Video


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MIT-nanoMIT is constructing, at the heart of the campus, a new 200,000-square-foot center for nanoscience and nanotechnology. This advanced facility will be a place for tinkering with atoms, one by one—and for constructing, from these fantastically small building blocks, the innovations of the future. Watch the MIT Video then Read More …

 

Read More

“Science is not only the disciple of Reason, but also one of Romance and Passion ~ Stephen B. Hawking

Nanotechnology is so small it’s measured in billionths of meters, and it is revolutionizing every aspect of our lives … Dictionary Series - Science: nanotechnology

The past 70 years have seen the way we live and work transformed by two tiny inventions. The electronic transistor and the microchip are what make all modern electronics possible, and since their development in the 1940s they have been getting smaller. Today, one chip can contain as many as 5 billion transistors. If cars had followed the same development pathway, we would now be able to drive them at 300,000 mph and they would cost just $6.00 (US) each.AmorChem Nanotechnology-300x200

But to keep this progress going we need to be able to create circuits on the extremely small, nanometer scale. A nanometer (nm) is one billionth of a meter and so this kind of engineering involves manipulating individual atoms. We can do this, for example, by firing a beam of electrons at a material, or by vaporizing it and depositing the resulting gaseous atoms layer by layer onto a base.

Read More: Nanotechnology is Changing EVERYTHING … Health Care, Clean Energy, Clean Water, Quantum Computing …

Be sure to ‘Follow Us’ on Twitter for the Latest ‘Nano’ Updates, News and Research:

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Stanford University: Solving the “Storage Problem” for Renewable Energies: A New Cost Effective Re-Chargeable Aluminum Battery


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One of the biggest missing links in renewable energy is affordable and high performance energy storage, but a new type of battery developed at Stanford University could be the solution.

Solar energy generation works great when the sun is shining [duh…like taking a Space Mission to the Sun .. but only at night! :-)] and wind energy is awesome when it’s windy (double duh…), but neither is very helpful for the grid after dark and when the air is still. That’s long been one of the arguments against renewable energy, even if there are plenty of arguments for developing additional solar and wind energy installations without large-scale energy storage solutions in place. However, if low-cost and high performance batteries were readily available, it could go a long way toward a more sustainable and cleaner grid, and a pair of Stanford engineers have developed what could be a viable option for grid-scale energy storage.

With three relatively abundant and low-cost materials, namely aluminum, graphite, and urea, Stanford chemistry Professor Hongjie Dai and doctoral candidate Michael Angell have created a rechargeable battery that is nonflammable, very efficient, and has a long lifecycle.

“So essentially, what you have is a battery made with some of the cheapest and most abundant materials you can find on Earth. And it actually has good performance. Who would have thought you could take graphite, aluminum, urea, and actually make a battery that can cycle for a pretty long time?” – Dai

A previous version of this rechargeable aluminum battery was found to be efficient and to have a long life, but it also employed an expensive electrolyte, whereas the latest iteration of the aluminum battery uses urea as the base for the electrolyte, which is already produced in large quantities for fertilizer and other uses (it’s also a component of urine, but while a pee-based home battery might seem like just the ticket, it’s probably not going to happen any time soon).

According to Stanford, the new development marks the first time urea has been used in a battery, and because urea isn’t flammable (as lithium-ion batteries are), this makes it a great choice for home energy storage, where safety is of utmost importance. And the fact that the new battery is also efficient and affordable makes it a serious contender when it comes to large-scale energy storage applications as well.

“I would feel safe if my backup battery in my house is made of urea with little chance of causing fire.” – Dai

According to Angell, using the new battery as grid storage “is the main goal,” thanks to the high efficiency and long life cycle, coupled with the low cost of its components. By one metric of efficiency, called Coulombic efficiency, which measures the relationship between the unit of charge put into the battery and the output charge, the new battery is rated at 99.7%, which is high.WEF solarpowersavemoney-628x330

In order to meet the needs of a grid-scale energy storage system, a battery would need to last at least a decade, and while the current urea-based aluminum ion batteries have been able to last through about 1500 charge cycles, the team is still looking into improving its lifetime in its goal of developing a commercial version.

The team has published some of its results in the Proceedings of the National Academy of Sciences, under the title “High Coulombic efficiency aluminum-ion battery using an AlCl3-urea ionic liquid analog electrolyte.”

 

PNL Battery Storage Systems 042016 rd1604_batteriesGrid-scale energy storage to manage our electricity supply would benefit from batteries that can withstand repeated cycling of discharging and charging. Current lithium-ion batteries have lifetimes of only 1,000-3,000 cycles. Now a team of researchers from Stanford University, Taiwan, and China have made a research prototype of an inexpensive, safe aluminum-ion battery that can withstand 7,500 cycles. In the aluminum-ion battery, one electrode is made from affordable aluminum, and the other is composed of carbon in the form of graphite.

Read: A step towards new, faster-charging, and safer batteries

 

Creating a Life-Saving, Blood-Repellent Super Material – Revolutionizing Medical Implants: Colorado State University


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Briefly

  • Biomedical engineers and materials scientists have developed a “superhemophobic” surface treatment for titanium that repels liquids including blood, plasma, and water.
  • The result is a surface that completely repels any liquid with which it would come in contact – a material that could revolutionize medical implants.

GOODBYE REJECTION

Implanted medical devices like stents, catheters, and titanium rods are essential, life-saving tools for patients around the world. Still, having a foreign object in the human body does pose its own risks – chiefly, having the body reject the object or increasing the risk of dangerous blood clots. A new collaboration between two distinct scientific disciplines is working toward making those risks a concern of the past.

Biomedical engineers and materials scientists from Colorado State University (CSU) have developed a “superhemophobic” surface treatment for titanium that repels liquids including blood, plasma, and water. The titanium is essentially studded with nanoscale tubes treated with a non-stick chemical. The result is a surface that completely repels any liquid with which it would come in contact. The team’s findings are published in Advanced Healthcare Materials.

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Fluorinated nanotubes provided the best superhemophobic surfaces in the CSU researchers’ experiments. Credit: Kota lab/Colorado State University

AN END TO CLOTTING

In cases where a body does reject a medical implant, the patient’s immune system detects the foreign object and mounts a defense against it, which can lead to serious inflammation and other complications. The real trick to the team’s surface is that the body doesn’t even recognize that it’s there. According to Arun Kota, assistant professor of mechanical engineering and biomedical engineering at CSU, “We are taking a material that blood hates to come in contact with, in order to make it compatible with blood.”

Regarding clotting, patients with medical implants often need to stay on a regimen of blood-thinning drugs to decrease the risk. However, blood thinners are not guaranteed to work, and they also carry the risk of leading to excessive bleeding due to the prevention of even beneficial clotting near wounds. As Ketul Popat, associate professor of mechanical engineering and biomedical engineering at CSU explains, “The reason blood clots is because it finds cells in the blood to go to and attach.” He continues, “if we can design materials where blood barely contacts the surface, there is virtually no chance of clotting.”

This material is only in its earliest stages of development. Should the team’s findings hold up to further scrutinization, these life-saving medical devices could be given an unprecedented boost in safety.

New organic-inorganic material creates more flexible, efficient technologies ~ For Solar Cells, Thermo-electric Devices and LED’s


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Credit: ACS

An organic-inorganic hybrid material may be the future for more efficient technologies that can generate electricity from either light or heat or devices that emit light from electricity.

Florida State University College of Engineering Assistant Professor Shangchao Lin has published a new paper in the journal ACS Nano that predicts how an organic-inorganic hybrid material called organometal halide perovskites could be more mechanically flexible than existing silicon and other inorganic materials used for , and light-emitting diodes.

In a separate study, Lin found that they might be more energy efficient as well.

“We’re addressing this from a theoretical perspective,” Lin said. “Nobody has really looked at the mechanical and thermal properties of this new material and how it could be used.”

Through mathematical simulations, Lin found that organic-inorganic hybrid perovskites should be extremely malleable and flexible. Although plenty of researchers have looked at perovskites for energy technologies, they did not think they were viable for certain devices because of their crystal structure. Scientists thought they would shatter if used for something like a solar panel.

However, Lin found that hybrid perovskites are predicted to fracture slowly through a crystalline-to-amorphous transition, which would make them very damage-tolerant.

Before mechanical failure, they might absorb twice as much elastic energy from external loading than currently used materials in electronic devices, such as silicon and gallium arsenide.

In a previous paper published in the journal Advanced Functional Materials, Lin and his team predicted that hybrid perovskites possess very due to the organic component. This could make them ideal materials for high efficiency thermoelectric energy conversion.

Specifically, his work suggested that hybrid perovskites are twice as efficient as the current state-of-art thermoelectric material, bismuth telluride, which is very expensive and composed of rare-earth elements.

“The amazing found in perovskites has put it at the frontier of material discovery,” Lin said. “Even more exciting, -based solar cells are four times as efficient, in terms of quantum yield, than polymer-based ones. They are also as efficient as the current, mainstream but are much more flexible and cheaper to make from a solution phase through a procedure very similar to inkjet printing.”

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Read More About: Will New Method of Making Perovskites Solar Cells Make Solar Energy More Efficient – Less Costly?

Lin hopes to follow these two studies by teaming with experimental chemists, material scientists and device engineers who could put his theoretical framework to the test.

“Computational materials-by-design will be a powerful predicting tool for researchers at FSU and at other universities and industry to use as they move forward in this field,” he said.

Explore further: Discovery of new crystal structure holds promise for optoelectronic devices

More information: Mingchao Wang et al. Anisotropic and Ultralow Phonon Thermal Transport in Organic-Inorganic Hybrid Perovskites: Atomistic Insights into Solar Cell Thermal Management and Thermoelectric Energy Conversion Efficiency, Advanced Functional Materials (2016). DOI: 10.1002/adfm.201600284

Jingui Yu et al. Probing the Soft and Nanoductile Mechanical Nature of Single and Polycrystalline Organic–Inorganic Hybrid Perovskites for Flexible Functional Devices, ACS Nano (2016). DOI: 10.1021/acsnano.6b05913

Harvard University: “Holy Grail” Metallic Hydrogen Is Going to Change Everything … from Space Travel to Energy


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The substance has the potential to revolutionize everything from space travel to the energy grid.

Two Harvard scientists have succeeded in creating an entirely new substance long believed to be the “holy grail” of physics — metallic hydrogen, a material of unparalleled power that could one day propel humans into deep space. The research was published Thursday in the journal Science.

Scientists created the metallic hydrogen by pressurizing a hydrogen sample to more pounds per square inch than exists at the center of the Earth. This broke the molecule down from its solid state and allowed the particles to dissociate into atomic hydro

The best rocket fuel we currently have is liquid hydrogen and liquid oxygen, burned for propellant. The efficacy of such substances is characterized by “specific impulse,” the measure of impulse fuel can give a rocket to propel it forward.

“People at NASA or the Air Force have told me that if they could get an increase from 450 seconds [of specific impulse] to 500 seconds, that would have a huge impact on rocketry,” Isaac Silvera, the Thomas D. Cabot Professor of the Natural Sciences at Harvard University, told Inverse by phone. “If you can trigger metallic hydrogen to recover to the molecular phase, [the energy release] calculated for that is 1700 seconds.”

Metallic hydrogen could potentially enable rockets to get into orbit in a single stage, even allowing humans to explore the outer planets. Metallic hydrogen is predicted to be “metastable” — meaning if you make it at a very high pressure then release it, it’ll stay at that pressure. A diamond, for example, is a metastable form of graphite. If you take graphite, pressurize it, then heat it, it becomes a diamond; if you take the pressure off, it’s still a diamond. But if you heat it again, it will revert back to graphite.

Scientists first theorized atomic metallic hydrogen a century ago. Silvera, who created the substance along with post-doctoral fellow Ranga Dias, has been chasing it since 1982 and working as a professor of physics at the University of Amsterdam.

Metallic hydrogen has also been predicted to be a high- or possibly room-temperature superconductor. There are no other known room-temperature superconductors in existence, meaning the applications are immense — particularly for the electric grid, which suffers for energy lost through heat dissipation. It could also facilitate magnetic levitation for futuristic high-speed trains; substantially improve performance of electric cars; and revolutionize the way energy is produced and stored.

But that’s all still likely a couple of decades off. The next step in terms of practical application is to determine if metallic hydrogen is indeed metastable. Right now Silvera has a very small quantity. If the substance does turn out to be metastable, it might be used to create room-temperature crystal and — by spraying atomic hydrogen onto the surface —use it like a seed to grow more, the way synthetic diamonds are made.

Photos via Nature

Graphene-Enhanced ski jackets ~ Directa Plus and Colmar launch second collection


directa-plus-colmar-graphene-ski-jacketDirecta Plus, ( Directs Plus ) a producer and supplier of graphene-based products, has announced that Colmar, the high-end sportswear company, has launched a new collection of ski jackets containing the Company’s graphene-based products.

 

 

The new Technologic G+ ski jacket is the second Colmar  (Colmar Sports Wear)  collection to contain Directa’s Graphene Plus (G+) and follows the ski-suit of the first capsule collection, worn by the French national ski team for multiple successful tournaments.

The new collection consists of three ski jackets with the inclusion of Directa’s G+ graphene technology. Directa Plus’ ability to supply tailor-made graphene-based products has enabled the incorporation of G+ with different textiles in each jacket based on the requirement of the particular garment:

  • the Technologic G+ jacket is padded with wadding printed with G+
  • the Bormio G+ jacket (based on a design originally created for the 1985 Ski World Cup in Bormio) has an outer shell made with a membrane containing G+
  • the Guaina Zeno G+ jacket (based on a design created for the Italian ski champion Zeno Colò in the 1950s) has a G+ lining

It was explained that the key benefit of incorporating G+ is that it enables the fabric to act as a filter between the body and the external environment, ensuring the ideal temperature for the wearer.

Due to the thermal conductive properties of graphene, the warmth produced by the human body is preserved and distributed evenly in cold climates, yet dispersed in warm climates, and allows an even body temperature during physical activity. Fabrics treated with Graphene Plus are also electrostatic and bacteriostatic. If placed on the outside of the garment, such as with the ski suit worn by the French national ski team, G+ reduces the friction with air and water to enable top sporting performance.

Source: Finance Yahoo

 

Nano-Engineered Surfaces that Prevent Frost formation with (With YouTube Video)


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Frost and ice accumulation result in significant decreases in the performance of ships, wind turbines, and heat exchangers. The use of active chemical, thermal, and mechanical methods of ice removal is time consuming and costly in operation. The development of passive methods to inhibit condensation, frost and ice formation is an attractive alternative.

 

Researchers like Konrad Rykaczewski, an assistant professor at School for Engineering of Matter, Transport and Energy at Arizona State University, focus on understanding the micro- and nanoscale mechanism of frost and ice accumulation on nanoengineered anti-frost and anti-icing superhydrophobic and lubricant impregnated surfaces.

Such nanoengineered surfaces possess special wetting properties that can not only efficiently repel or attract liquids like water and oils but can also prevent formation of biofilms, ice, and other detrimental crystals.Rykaczewski and his PhD student Xiaoda Sun have found a new way to inhibit condensate and frost nucleation that is compatible with the icephobic coatings as well as current de-icing techniques.

Reporting their findings in ACS Nano (“Suppression of Frost Nucleation Achieved Using the Nanoengineered Integral Humidity Sink Effect”), the two scientists systematically explore how frost growth can be inhibited by controlling water vapor concentration using porous bilayer coatings infused with a hygroscopic liquid, and they revealed intriguing size effects in this system.

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Schematic of the nanoporous bilayer coating and results of experiments with the mesh size getting smaller. (Reprinted with permission by American Chemical Society) (click on image to enlarge)

 

“The first step in condensation and frost growth is formation of nanoscale nuclei on the surface,” Rykaczewski explains to Nanowerk. “From thermodynamics, there are two ways to prevent or slow nucleation: changing the surface chemistry so that molecules do not like to aggregate on it – for water making surface hydrophobic – or decreasing the concentration of water molecules above the surface.”He points out that the first approach is relatively easy and has been tried extensively: it basically requires a surface to be coated with something like Teflon. Unfortunately, small defects on the surface (think little scratches) can facilitate nucleation.”Instead of hoping for perfect surfaces, we decided to explore whether it would be possible to design coatings that could alter nucleation using the second approach,” says Rykaczewski. “Specifically, we wanted to make a coating that would alter water vapor concentration above it.

 

“Based on their earlier work (Langmuir, “Inhibition of Condensation Frosting by Arrays of Hygroscopic Antifreeze Drops”), the researchers thought that this could be achieved by engineering a process referred to as humidity sink effect. This phenomena occurs when a hygroscopic (i.e. highly water vapor absorbing) liquid is exposed to air.It has been known for a while that when a droplet of such liquid is placed on a cold surface, condensation or frost form everyone but within a region around the drop where the droplet ‘sucks’ up water vapor (see video below) One can do this experiment by putting a salty water drop in the freezer.

“In our previous work, we showed that by placing such drops close enough for the nucleation free regions to overlap, condensation and frost can be prevented over entire surface,” Rykaczewski notes. “In our present paper we used an idea of bi-layer coatings with porous outside separating a hygroscopic liquid infused layer. Analogously to drops, when pores with the liquid are spaced close enough, nucleation does not occur on the outside.”

“Interestingly” he continues, “the model we developed suggests that as the size and spacing of these pores decreases to nanoscale, the concentration above the surface becomes uniform, independent of the hole size, and equal to that set by the hygroscopic liquid (usually would increase in between pores). This is really intriguing: when the pore size is optimized, the system behaves as if the membrane was not there.”This means that in order to nucleate, the saturation concentration and that set by the hygroscopic liquid need to be nearly equal. This happens at very low temperatures, and as a result the team did not observe any nucleation until about -40°C when the sample was in 100% water-saturated air at 25°C (i.e. the dew point is depressed by 65°C).

“We proved these theoretical predictions experimentally and showed that by decreasing the pore size/spacing from millimeters to nanometers while keeping total ‘open’ area the same, we can continually decrease the dew point to -40°C,” says Rykaczewski. “This of course lasts only until the liquid is diluted, but from our experiments this period is long enough to get airplanes through icing danger zone during their ascend and descent.”One of the primary applications of these icephobic coating is in the aviation industry. In another previous work (Advanced Materials Interfaces, “Bioinspired Stimuli-Responsive and Antifreeze-Secreting Anti-Icing Coatings”), the team showed that bi-layer coatings infused with antifreeze can prevent multiple forms of icing while saving a lot of antifreeze.Most antifreezes are hygrosocopic, so by optimizing the coating based on this work researchers can inhibit condensation in even severe conditions (down to -40°C).”What we hope for is to test our coatings on small systems, for example UAVs that are used in search and rescue missions or by navy to look for icebergs in the arctic,” notes Rykaczewski.

Contributor: Michael Berger/ Nanowerk

Scientists Determine Precise 3-D Location and Identity of All 23,000 Atoms in a Nanoparticle ~ Cool Video!





The atomic composition of an iron-platinum nanoparticle revealed. This is an overview of the 3-D positions of individual atoms, with iron atoms in red and platinum atoms in blue. It then splits apart into the large and small grains that compose the nanoparticle. (Credit: Colin Ophus and Florian Niekiel, Berkeley Lab) Niekiel, Berkeley Lab)

Berkeley Lab researchers help to map iron-platinum particle in unprecedented detail

Scientists used one of the world’s most powerful electron microscopes to map the precise location and chemical type of 23,000 atoms in an extremely small particle made of iron and platinum.

The 3-D reconstruction reveals the arrangement of atoms in unprecedented detail, enabling the scientists to measure chemical order and disorder in individual grains, which sheds light on the material’s properties at the single-atom level. Insights gained from the particle’s structure could lead to new ways to improve its magnetic performance for use in high-density, next-generation hard drives.

Watch Video

What’s more, the technique used to create the reconstruction, atomic electron tomography (which is like an incredibly high-resolution CT scan), lays the foundation for precisely mapping the atomic composition of other useful nanoparticles. This could reveal how to optimize the particles for more efficient catalysts, stronger materials, and disease-detecting fluorescent tags.

Microscopy data was obtained and analyzed by scientists from the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) at the Molecular Foundry, in collaboration with Foundry users from UCLA, Oak Ridge National Laboratory, and the United Kingdom’s University of Birmingham. The research is reported Feb. 2 in the journal Nature.

Atoms are the building blocks of matter, and the patterns in which they’re arranged dictate a material’s properties. These patterns can also be exploited to greatly improve a material’s function, which is why scientists are eager to determine the 3-D structure of nanoparticles at the smallest scale possible.

“Our research is a big step in this direction. We can now take a snapshot that shows the positions of all the atoms in a nanoparticle at a specific point in its growth. This will help us learn how nanoparticles grow atom by atom, and it sets the stage for a materials-design approach starting from the smallest building blocks,” says Mary Scott, who conducted the research while she was a Foundry user, and who is now a staff scientist. Scott and fellow Foundry scientists Peter Ercius and Colin Ophus developed the method in close collaboration with Jianwei Miao, a UCLA professor of physics and astronomy.

Their nanoparticle reconstruction builds on an achievement they reported last year in which they measured the coordinates of more than 3,000 atoms in a tungsten needle to a precision of 19 trillionths of a meter (19 picometers), which is many times smaller than a hydrogen atom. Now, they’ve taken the same precision, added the ability to distinguish different elements, and scaled up the reconstruction to include tens of thousands of atoms.

Importantly, their method maps the position of each atom in a single, unique nanoparticle. In contrast, X-ray crystallography and cryo-electron microscopy plot the average position of atoms from many identical samples. These methods make assumptions about the arrangement of atoms, which isn’t a good fit for nanoparticles because no two are alike.

“We need to determine the location and type of each atom to truly understand how a nanoparticle functions at the atomic scale,” says Ercius.

A TEAM approach

TEAM

The scientists’ latest accomplishment hinged on the use of one of the highest-resolution transmission electron microscopes in the world, called TEAM I. It’s located at the National Center for Electron Microscopy, which is a Molecular Foundry facility. The microscope scans a sample with a focused beam of electrons, and then measures how the electrons interact with the atoms in the sample. It also has a piezo-controlled stage that positions samples with unmatched stability and position-control accuracy.

The researchers began growing an iron-platinum nanoparticle from its constituent elements, and then stopped the particle’s growth before it was fully formed. They placed the “partially baked” particle in the TEAM I stage, obtained a 2-D projection of its atomic structure, rotated it a few degrees, obtained another projection, and so on. Each 2-D projection provides a little more information about the full 3-D structure of the nanoparticle.

They sent the projections to Miao at UCLA, who used a sophisticated computer algorithm to convert the 2-D projections into a 3-D reconstruction of the particle. The individual atomic coordinates and chemical types were then traced from the 3-D density based on the knowledge that iron atoms are lighter than platinum atoms. The resulting atomic structure contains 6,569 iron atoms and 16,627 platinum atoms, with each atom’s coordinates precisely plotted to less than the width of a hydrogen atom.

Translating the data into scientific insights

Computer algorithms developed by Colin Ophus enabled the scientists to decipher the atomic structure of the nanoparticle, which shed light on how the atoms arrange themselves into an ordered structure with optimal magnetic properties. (Credit: Marilyn Chung)

Interesting features emerged at this extreme scale after Molecular Foundry scientists used code they developed to analyze the atomic structure. For example, the analysis revealed chemical order and disorder in interlocking grains, in which the iron and platinum atoms are arranged in different patterns. This has large implications for how the particle grew and its real-world magnetic properties. The analysis also revealed single-atom defects and the width of disordered boundaries between grains, which was not previously possible in complex 3-D boundaries.

“The important materials science problem we are tackling is how this material transforms from a highly randomized structure, what we call a chemically-disordered structure, into a regular highly-ordered structure with the desired magnetic properties,” says Ophus.

To explore how the various arrangements of atoms affect the nanoparticle’s magnetic properties, scientists from DOE’s Oak Ridge National Laboratory ran computer calculations on the Titan supercomputer at ORNL—using the coordinates and chemical type of each atom—to simulate the nanoparticle’s behavior in a magnetic field. This allowed the scientists to see patterns of atoms that are very magnetic, which is ideal for hard drives. They also saw patterns with poor magnetic properties that could sap a hard drive’s performance.

“This could help scientists learn how to steer the growth of iron-platinum nanoparticles so they develop more highly magnetic patterns of atoms,” says Ercius.

Adds Scott, “More broadly, the imaging technique will shed light on the nucleation and growth of ordered phases within nanoparticles, which isn’t fully theoretically understood but is critically important to several scientific disciplines and technologies.”

The Molecular Foundry is a DOE Office of Science User Facility. The research was primarily supported by the Department of Energy’s Office of Science.

###

Lawrence Berkeley National Laboratory addresses the world’s most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab’s scientific expertise has been recognized with 13 Nobel Prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy’s Office of Science. For more, visit http://www.lbl.gov.

DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

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