Posts belonging to Category coatings

TriboElectricity, The Green Energy Source

Researchers from Clemson’s Nanomaterials Institute (CNI) are one step closer to wirelessly powering the world using triboelectricity, a green energy source. In March 2017, a group of physicists at CNI invented the ultra-simple triboelectric nanogenerator or U-TENG, a small device made of plastic and tape that generates electricity from motion and vibrations. When the two materials are brought together — through such actions as clapping the hands or tapping feet — they generate voltage that is detected by a wired, external circuit. Electrical energy, by way of the circuit, is then stored in a capacitor or a battery until it’s needed.

Nine months later, in a paper published in the journal Advanced Energy Materials, the researchers reported that they had created a wireless TENG, called the W-TENG, which greatly expands the applications of the technology. The W-TENG was engineered under the same premise as the U-TENG using materials that are so opposite in their affinity for electrons that they generate a voltage when brought in contact with each other.

In the W-TENG, plastic was swapped for a multipart fiber made of graphene — a single layer of graphite, or pencil lead — and a biodegradable polymer known as polylactic acid (PLA). PLA on its own is great for separating positive and negative charges, but not so great at conducting electricity, which is why the researchers paired it with graphene. Kapton tape, the electron-grabbing material of the U-TENG, was replaced with Teflon, a compound known for coating nonstick cooking pans.

After assembling the graphene-PLA fiber, the researchers pulled it into a 3-D printer and the W-TENG was born. The end result is a device that generates a maximum of 3,000 volts — enough to power 25 standard electrical outlets or, on a grander scale, smart-tinted windows or a liquid crystal display (LCD) monitor. Because the voltage is so high, the W-TENG generates an electric field around itself that can be sensed wirelessly. Its electrical energy, too, can be stored wirelessly in capacitors and batteries.

It cannot only give you energy, but you can use the electric field also as an actuated remote. For example, you can tap the W-TENG and use its electric field as a ‘button’ to open your garage door, or you could activate a security system — all without a battery, passively and wirelessly,” said Sai Sunil Mallineni, the first author of the study and a Ph.D. student in physics and astronomy.


Hard Material With Self-Healing Capability

Imagine a cellphone that can heal from cuts and scratches just like the human body can. For Chinese researcher Ming Yang and his team at the Harbin Institute of Technology, it’s not really a question of imagining anymore: They have developed a new kind of smart coating that manages to be both soft and hard, not unlike our own skin.

We designed a self-healing coating with a hardness that even approaches tooth enamel by mimicking the structure of epidermis,” Yang says. “This is the most desirable property combination in the current self-healing materials and coatings.”

As described in a paper published Wednesday in ACS Nano, this new material is far from the first smart coating, with previous research looking at both soft and hard coating options. Yang says there’s serious global need for better self-healing materials.

Nowadays people always talk about environment and energy,” he adds. “A self-healing material can help save a lot of money and energy using a smart, environmental friendly way. But the current self-healing materials and coatings are typically soft and wear out quickly. This can bring potential problems about the management of plastic waste.

This new material could solve those waste problems, as it comes closer than any predecessor to combining the flexibility of a soft coating and the resilience of a hard coating, without the short lifespan of the former or the brittleness of the latter. This could be the best of both worlds.

The trick is to use artificial materials in nature’s way,” explains Yang. “The multilayer structure is the key. By placing a hard layer containing graphene oxide on top of a soft layer, we create a smart hybridization you can get the most out of.”

The graphene oxide material used in the coating’s top layer is harder than skin cells, offering a toughness closer to that of teeth enamel. The amazing thing, according to Yang, is that the coating’s hard and soft layers are able to work together to create healing properties that neither could accomplish on its own.


Adding Graphene To Silicon Electrodes Double Lithium Batteries Life

New research led by WMG (academic department), at the University of Warwick (UK) has found an effective approach to replacing graphite in the anodes of lithium-ion batteries using silicon, by reinforcing the anode’s structure with graphene girders. This could more than double the life of rechargeable lithium-ion based batteries by greatly extending the operating lifetime of the electrode, and also increase the capacity delivered by those batteries.

Graphite has been the default choice of active material for anodes in lithium—ion batteries since their original launch by Sony but researchers and manufacturers have long sought a way to replace graphite with silicon, as it is an abundantly available element with ten times the gravimetric energy density of graphite. Unfortunately, silicon has several other performance issues that continue to limit its commercial exploitation.

Due to its volume expansion upon lithiation silicon particles can electrochemically agglomerate in ways that impede further charge-discharge efficiency over time. Silicon is also not intrinsically elastic enough to cope with the strain of lithiation when it is repeatedly charged, leading to cracking, pulverisation and rapid physical degradation of the anode’s composite microstructure. This contributes significantly to capacity fade, along with degradation events that occur on the counter electrode – the cathode. To use the mobile phones as an example, this is why we have to charge our phones for a longer and longer time, and it is also why they don’t hold their charge for as long as when they are new.

However new research, led by Dr Melanie Loveridge in WMG at the University of Warwick, has discovered, and tested, a new anode mixture of silicon and a form of chemically modified graphene which could resolve these issues and create viable silicon anode lithium-ion batteries. Such an approach could be practically manufactured on an industrial scale and without the need to resort to nano sizing of silicon and its associated problems.

The new research has been published in Nature Scientific Reports.


Thin And Highly Insulating Walls Lower Heating Costs

Better thermal insulation means lower heating costs – but this should not be at the expense of exciting architecture. A new type of brick filled with aerogel could make thin and highly insulating walls possible in the future – without any additional insulation layer.

The calculation is simple: the better a building is insulated, the less heat is lost in winter – and the less energy is needed to achieve a comfortable room temperature. No wonder, then, that the Swiss Federal Office of Energy (SFOE) regularly raises the requirements for building insulation.

In order to achieve the same insulation values as a 165 mm thick wall of aerobricks, a wall of perlite bricks must be 263 mm thick – and a wall of non-insulating bricks even more than one meter!

Traditionally, the insulating layers are applied to the finished walls. Increasingly, however, self-insulating bricks are being used – saving both work steps and costs and opening up new architectural possibilities. Insulating bricks offer a workable compromise between mechanical and thermal properties and are also suited for multi-storey buildings. They are already available on the market in numerous models: some have multiple air-filled chambers, others have larger cavities filled with insulating materials such as pearlite, mineral wool or polystyrene. Their thermal conductivity values differ depending on the structure and filling material. In order to reach the insulation values of walls with seperate insulating layers, the insulating bricks are usually considerably thicker than normal bricks.

Empa researchers have now replaced Perlite in insulating bricks with Aerogel: a highly porous solid with very high thermal insulation properties that can withstand temperatures of up to 300°C (see box). It is not a novel material for the researchers: they have already used it to develop a high-performance insulating plaster which, among other things, allows historical buildings to be renovated energetically without affecting their appearance.

Together with his colleagues, Empa researcher Jannis Wernery from the research department «Building Energy Materials and Components» has developed a paste-like mixture of aerogel particles to be used as filler material for the brick. «The material can easily be filled into the cavities and then joins with the clay of the bricks», says Wernery. «The aerogel stays in the bricks – you can work with them as usual.» The «Aerobrick» was born.


Fabric Made Of Nanofibers With Embedded OLED

In South Korea, Professor Kyung Cheol Choi from the School of Electrical Engineering (KAIST)  and his team succeeded in fabricating highly efficient Organic Light-Emitting Diodes (OLEDs) on an ultra-thin fiber. The team expects the technology, which produces high-efficiency, long-lasting OLEDs, can be widely utilized in wearable displays. Existing fiber-based wearable displays’ OLEDs show much lower performance compared to those fabricated on planar substrates. This low performance caused a limitation for applying it to actual wearable displays.

In order to solve this problem, the team designed a structure of OLEDs compatible to fiber and used a dip-coating method in a three-dimensional structure of fibers. Through this method, the team successfully developed efficient OLEDs that are designed to last a lifetime and are still equivalent to those on planar substrates.
The team identified that solution process planar OLEDs can be applied to fibers without any reduction in performance through the technology. This fiber OLEDs exhibited luminance and current efficiency values of over 10,000 cd/m^2(candela/square meter) and 11 cd/A (candela/ampere).
The team also verified that the fiber OLEDs withstood tensile strains of up to 4.3% while retaining more than 90% of their current efficiency. In addition, they could be woven into textiles and knitted clothes without causing any problems.Moreover, the technology allows for fabricating OLEDs on fibers with diameters ranging from 300㎛ down to 90㎛, thinner than a human hair, which attests to the scalability of the proposed fabrication scheme.
Noting that every process is carried out at a low temperature (~105℃), fibers vulnerable to high temperatures can also employ this fabrication scheme.
Professor Choi said, “Existing fiber-based wearable displays had limitations for applicability due to their low performance. However, this technology can fabricate OLEDs with high performance on fibers. This simple, low-cost process opens a way to commercialize fiber-based wearable displays.”

In 2025 Humanity Could Benefit From A Major New Source Of Clean Power

An international project to generate energy from nuclear fusion has reached a key milestone, with half of the infrastructure required now built. Bernard Bigot, the director-general of the International Thermonuclear Experimental Reactor (Iter), the main facility of which is based in southern France, said the completion of half of the project meant the effort was back on track, after a series of difficulties. This would mean that power could be produced from the experimental site from 2025.

Nuclear fusion occurs when two atoms combine to form a new atom and a neutron. The atoms are fired into a plasma where extreme temperatures overcome their repulsion and forces them together. The fusion releases about four times the energy produced when an atom is split in conventional nuclear fission

The effort to bring nuclear fusion power closer to operation is backed by some of the world’s biggest developed and emerging economies, including the EU, the US, China, India, Japan, Korea and Russia. However, a review of the long-running project in 2013 found problems with its running and organisation. This led to the appointment of Bigot, and a reorganisation that subsequent reviews have broadly endorsed.

Fusion power is one of the most sought-after technological goals in the pursuit of clean energy. Nuclear fusion is the natural phenomenon that powers the sun, converting hydrogen into helium atoms through a process that occurs at extreme temperatures.

Replicating that process on earth at sufficient scale could unleash more energy than is likely to be needed by humanity, but the problem is creating the extreme conditions necessary for such reactions to occur, harnessing the resulting energy in a useful way, and controlling the reactions once they have been induced.

The Iter project aims to use hydrogen fusion, controlled by large superconducting magnets, to produce massive heat energy which would drive turbines – in a similar way to the coal-fired and gas-fired power stations of today – that would produce electricity. This would produce power free from carbon emissions, and potentially at low cost, if the technology can be made to work at a large scale.

For instance, according to Iter scientists, an amount of hydrogen the size of a pineapple could be used to produce as much energy as 10,000 tonnes of coal.


Thermoelectric Power Generation

Thermoelectric (TE) materials could play a key role in future technologies. Although the applications of these remarkable compounds have long been explored, they are mostly limited to high-temperature devices. Recently, researchers at Osaka University, in collaboration with Hitachi, Ltd., developed a new TE material with an improved power factor at room temperature. Their study, published in Physica Status Solidi RRL, could help bring these materials out of the high-temperature niche and into the mainstream.

TE materials display the thermoelectric effect: apply heat on one side, and an electric current starts to flow. Conversely, run an external current through the device, and a  temperature gradient forms; i.e., one side becomes hotter than the other. By interconverting heat and electricity, TE materials can be used as either power generators (given a heat source) or refrigerators (given a power supply).

The ideal TE material combines high electrical conductivity, allowing the current to flow, with low thermal conductivity, which prevents the temperature gradient from evening out. The power generation performance mainly depends on the “power factor,” which is proportional to both electrical conductivity and a term called the Seebeck coefficient.

Unfortunately, most TE materials are often based on rare or toxic elements,” according to study co-author Sora-at Tanusilp. “To address this, we combined silicon – which is common in TE materials – with ytterbium, to create ytterbium silicide [YbSi2]. We chose ytterbium over other metals for several reasons. First, its compounds are good electrical conductors. Second, YbSi2 is non-toxic. Moreover, this compound has a specific property called valence fluctuation that make it a good TE material at low temperatures.


Virgin Hyperloop One’s System Over 240 mph (387 km/h)

In a recent test, Virgin Hyperloop One‘s system beat all previous speed records, hitting nearly 387 kilometers per hour (240 miles per hour). With Richard Branson now in their corner, the company could dominate the future of hyperloop transportation. On December 18, Virgin Hyperloop One announced the completion of third phase testing on the DevLoop, the world’s first full-scale hyperloop test site. During these tests, the system clocked a lightning-fast speed of nearly 387 kmh (240 mph), breaking the 355 kmh (220 mph) hyperloop speed record set by Elon Musk’s hyperloop in August.

During this phase of testing, the company experimented with using a new airlock that helps test pods transition between atmospheric and vacuum conditions. By combining magnetic levitation, extremely low aerodynamic drag, and the level of air pressure experienced at 200,000 feet above sea level, the system proved that it is capable of reaching airline speeds over long distances.


The recent phase three testing continues to prove the incredible persistence and determination of our DevLoop team — the close to 200 engineers, machinists, welders, and fabricators who collaborated to make hyperloop a reality today,” Josh Giegel, Virgin Hyperloop One’s co-founder and chief technology officer, stated in a press release announcing the new hyperloop speed record.


Gilded fuel cells boost electric car efficiency

To make modern-day fuel cells less expensive and more powerful, a team led by Johns Hopkins chemical engineers has drawn inspiration from the ancient Egyptian tradition of gilding. Egyptian artists at the time of King Tutankhamun often covered cheaper metals (copper, for instance) with a thin layer of a gleaming precious metal such as gold to create extravagant masks and jewelry. In a modern-day twist, the Johns Hopkins-led researchers have applied a tiny coating of costly platinum just one nanometer thick—100,000 times thinner than a human hair—to a core of much cheaper cobalt. This microscopic marriage could become a crucial catalyst in new fuel cells that generate electric current to power cars and other machines.

The new fuel cell design would save money because it would require far less platinum, a very rare and expensive metal that is commonly used as a catalyst in present-day fuel-cell electric cars. The researchers, who published their work earlier this year in Nano Letters, say that by making electric cars more affordable, this innovation could curb the emission of carbon dioxide and other pollutants from gasoline– or diesel-powered vehicles.

This technique could accelerate our launch out of the fossil fuel era,” said Chao Wang, a Johns Hopkins assistant professor in the Department of Chemical and Biomolecular Engineering and senior author of the study. “It will not only reduce the cost of fuel cells. It will also improve the energy efficiency and power performance of clean electric vehicles powered by hydrogen.”

In their journal article, the authors tipped their hats to the ancient Egyptian artisans who used a similar plating technique to give copper masks and other metallic works of art a lustrous final coat of silver or gold.The idea,” Wang said, “is to put a little bit of the precious treasure on top of the cheap stuff.”

He pointed out that platinum, frequently used in jewelry, also is a critical material in modern industry. It catalyzes essential reactions in activities including petroleum processing, petrochemical synthesis, and emission control in combustion vehicles, and is used in fuel cells. But, he said, platinum’s high cost and limited availability have made its use in clean energy technologies largely impractical—until now.


Flying MotorBikes For Dubai Police

Dubai Police, already home to Lamborghini patrol cars and android officers, has decided to take to the skies in what can only be described as a flying motorbike.


The vehicle, called the Scorpion and designed by Russian tech company Hoversurf, relies on four propellers to stay airborne, with the rider crouched precariously close to the exposed blades. Capable of 40 mph and a travel time of 25 minutes, the single-seat craft, which can carry 600 lbs, can also operate autonomously.

After appearing at tech shows earlier this year, Dubai Police has decided to add one to its list of cutting-edge gadgets, all part of the force’s “smart city” plans.

Unveiled at Dubai’s Gitex Technology show, the Scorpion was presented alongside a new electric motorbike concept by Japanese firm Mikasa — firmly rooted to the ground, but with a top speed of 124 mph according to the police and looking like something out of the film “Tron.”

Swiss Army Knife NanoVaccine To Fight Tumors

Scientists are using their increasing knowledge of the complex interaction between cancer and the immune system to engineer increasingly potent anti-cancer vaccines.
Now researchers at the National Institute ofBiomedical Imaging and Bioengineering (NIBIB) have developed a synergistic nanovaccine packing DNA and RNA sequences that modulate the immune response, along with anti-tumor antigens, into one smallnanoparticle. The nanovaccine produced an immune response that specifically killed tumor tissue, while simultaneously inhibiting tumor-induced immune suppression. Together this blocked lung tumor growth in a mouse model of metastatic colon cancer.

Large particles (left) containing the DNA and RNA components are coated with electronically charged molecules that shrink the particle. The tumor-specific neoantigen is then complexed with the surface to complete construction of the nanovaccine.
Upper left: electron micrograph of large particle


The molecular dance between cancer and the immune system is a complex one and scientists continue to identify the specific molecular pathways that rev up or tamp down the immune system. Biomedical engineers are using this knowledge to create nanoparticles that can carry different molecular agents that target these pathways. The goal is to simultaneously stimulate the immune system to specifically attack the tumor while also inhibiting the suppression of the immune system, which often occurs in cancer patients. The aim is to press on the gas pedal of the immune system while also releasing the emergency brake.

A key hurdle is to design a system to reproducibly and efficiently create a nanoparticle loaded with multiple agents that synergize to mount an enhanced immune attack on the tumor. Engineers at the NIBIB report the development and testing of such a nanovaccine in the journal Nature Communications.


Glass Blocks Generate Electricity Using Solar Energy

Buildings consume more than forty percent of global electricity and reportedly cause at least a third of carbon emissions. Scientists want to cut this drastically – and create a net-zero energy future for new buildings. Build Solar want to help. The firm has created a glass brick containing small solar cells.


On top of this we have placed in some intelligent optics which are able to focus the incoming sunlight onto these solar cells almost throughout the day. When we do that we are able to generate a higher amount of electrical output from each solar cell that we are using,” says Dr Hasan Baig, founder of Build Solar.
As well as converting the sun’s power to electricity, the bricks have other abilities.
The product is aligned to provide three different things, including electricity, daylighting, and thermal insulation which is generally required by any kind of construction product. More importantly it is aesthetic in its look, so it fits in very well within the building architecture,” adds Dr Baig.
Using Building Integrated Photovoltaics, the technology would be used in addition to existing solar roof panels. The University of Exeter spin-off is fine-tuning the design, which works in many colours. The company says the product could be market ready by the end of next year.