Polymer coatings have self healing qualities

Materials that can repair themselves are generally a good thing, as they increase the lifespan of products created from them, and reduce the need for maintenance. Biorenewable polymers are also pretty likable, as they reduce or even eliminate the need for petroleum products in plastic production, replacing them with plant-derived substances. Michael Kessler, an Iowa State University associate professor of materials science and engineering, and an associate of the U.S. Department of Energy’s Ames Laboratory, is now attempting to combine the two.

Self-healing materials generally incorporate microcapsules containing a liquid healing agent, and catalyst elements, which are embedded within the material’s matrix. As cracks form within the matrix, the microcapsules rupture, releasing the healing agent. As soon as that agent encounters the catalyst, it hardens into three-dimensional polymer chains, thus filling and securing the cracks. Such technology has been used not only to create self-healing plastics, but also self-healing concrete.

Since 2005, Kessler has been working with Iowa State’s Prof. Richard Larock on the development of biorenewable polymers made from vegetable oils. Larock is the inventor of a process wherein bioplastics can be created that consist of 40 to 80 percent inexpensive natural oils – these plastics reportedly have very good thermal and mechanical properties, are good at dampening noises and vibrations, and are also very good at returning to their original shape when heated.

Kessler is now trying to create self-healing versions of these same plastics.

One thing he has deduced so far is that a healing agent for a tung oil-based polymer works too fast. Kessler and his colleagues are now working on slowing down the reactive process of that agent, while also developing biopolymer-friendly encapsulating techniques, and bio-based healing agents.

The big challenge, he says, is to match the 90 percent healing efficiency of standard synthetic composites.

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Visitors to last year’s World 2010 Expo in Shanghai might have noticed that the outer walls of the Italian pavilion were kind of… DIFFERENT. Although they felt solid, and looked like concrete when viewed from an angle, light was able to pass through them. How could it be possible? They were made from what the Italcementi Group refers to as “transparent cement,” and has trademarked as i.light. It’s definitely a unique substance, as it blurs the line between wall and window.

The material was created specifically for the pavilion, as architect Giampaolo Imbrighi wanted a building with transparent walls. While the exact fabrication method hasn’t been fully divulged, Italcementi states that it involves “an innovative cement/admixtures mix design.” That mixture reportedly bonds well with thermoplastic polymer resin, which is inserted into a matrix of 2-3 mm holes running through the width of each panel.

There are approximately 50 holes in each 500 x 1,000 x 50 mm (19.7 x 39 x 2 inch) panel, resulting in an overall transparency of about 20 percent – the pavilion also included semi-transparent panels, which had a transparency of 10 percent created by “modulating the insertion of the resins.”

Past attempts at similar materials have included placing fiber optic cables through a concrete mixture, although the Italcementi researchers claim that their product is much less expensive to produce, and allows light to enter from a greater number of angles.

Although i.light has yet to be made available for commercial use, it has already been suggested that buildings made with the material could save electricity that would otherwise be required for daytime lighting.

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New Teflon: stronger than diamonds (2:28)

Dec 7 – It is only one atom thick, but according to the Nobel prize winning scientists who discovered it, flourographene could soon be making a big impact. Stuart McDill reports.

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Scientists claim breakthrough

in antimatter hunt

Photo released by CERN on November 18, 2010 shows an image taken by the ALPHA annihilation detector showing untrapped antihydrogen atoms annihilating on the inner surface of the ALPHA trap. Photo: AP/CERN

Scientists claimed a breakthrough Thursday toward solving one of the biggest riddles of physics, trapping an “anti-atom” for the first time in a quest to understand what happened to all the antimatter that has vanished since the Big Bang.

An international team of physicists at the European Organisation for Nuclear Research, or CERN, managed to keep atoms of anti-hydrogen from disappearing long enough to demonstrate that they can be studied in the lab.

“For us it’s a big breakthrough because it means we can take the next step, which is to try to compare matter and antimatter,” the team’s spokesman, American scientist Jeffrey Hangst, said Thursday.

“This field is 20 years old and has been making incremental progress toward exactly this all along the way,” he added. “We really think that this was the most difficult step.”

Researchers have puzzled for decades over why antimatter seems to have disappeared from the universe.

Theory posits that matter and its opposite, antimatter — both are defined as having mass and taking up space — were created in equal amounts at the moment of the Big Bang, which spawned the universe some 13.7 billion years ago. While matter went on to become the building block of everything that exists, antimatter has all but disappeared except in the lab.

Hangst and his colleagues, who included scientists from Britain, Brazil, Canada, Israel and the United States, trapped 38 anti-hydrogen atoms individually for more than one tenth of a second, according to a paper published online Wednesday by the journal Nature.

Since their first success, the team has managed to hold the anti-atoms even longer.

“Unfortunately I can’t tell you how long, because we haven’t published the number yet,” Hangst said. “But I can tell you that it’s much, much longer than a tenth of a second. Within human comprehension on a real clock.”

Scientists have long been able to create individual particles of antimatter such as anti-protons, anti-neutrons and positrons — the opposite of electrons. Since 2002, they have also managed to create anti-atoms in large quantities, but until recently none could be trapped for long enough to study them, because atoms made of antimatter and matter annihilate each other in a burst of energy upon contact.

“It doesn’t help if they disappear immediately upon their creation,” said Hangst. “So the big goal has been to hold onto them.”

Two teams had been competing for that goal at CERN, the world’s largest physics lab best known for its $US10 billion smasher, the Large Hadron Collider. The collider, built deep under the Swiss-French border, wasn’t used for this experiment.

Hangst’s ALPHA team got there first, beating the rival ATRAP team led by Harvard physicist Gerald Gabrielse, who nevertheless welcomed the result.

“The atoms that were trapped were not yet trapped very long and in a very usable number, but one has to crawl before you sprint,” he said.

Many new techniques painstakingly developed over five years of experimental trial and error preceded the successful capture of anti-hydrogen.

To trap the anti-atoms inside an electromagnetic field and to stop them from annihilating atoms, researchers had to create anti-hydrogen at temperatures less than half a degree above absolute zero.

“Think of it as a marble rolling back and forth in a bowl,” said Hangst. “If the marble is rolling too fast (i.e. the anti-atom is too hot) it just goes over the edge.”

Next, scientists plan to conduct basic experiments on the anti-atom, such as shining a laser onto it and seeing how it behaves, he said.

“We have a chance to make a really precise comparison between a matter system and an antimatter system,” he said, “That’s unique, that’s never been done. That’s where we’re headed now.”

Hangst downplayed speculation that antimatter might someday be harnessed as a source of energy, or to create a powerful weapon, an idea popularised in Dan Brown’s best-selling novel “Angels and Demons”.

“It would take longer than the age of the universe to make one gram of antimatter,” he said, calling the process “a losing proposition because it takes much more energy to make antimatter than you get out of it.”

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Intel Turns to Light

to Transfer Data Inside PCs

// <![CDATA[// Jul 28, 2010 6:40 am

Intel on Tuesday announced it had developed a prototype interconnect that uses light to speed up data transmission inside computers at the speed of 50 gigabits per second.

Intel researchers said that the optical technology could ultimately replace the use of copper wires and electrons to carry data inside or around computers. An entire high-definition movie can be transmitted each second with the prototype, the researchers said.

The technology will also be able to carry data over longer distances than copper wires, Intel researchers said.

Intel’s chief technology officer Justin Rattner characterized the research prototype as a breakthrough in research as copper wires were reaching their limit. There is a wealth of data that needs to be moved, and transferring data at 10G bps or more over copper wires is becoming a challenge. Even if the data could be transferred over copper wires at that speed, there are distance trade-offs.

Optical interconnects solve that problem by allowing data transfers at much faster rates, and over longer distances, Rattner said on a conference call to discuss the technology.

“Photonics gives us the ability to move those mass quantities of data across the room… in a cost-effective matter,” Rattner said.

The photonics technology could potentially speed up data transfers within PCs or devices such as handhelds, where movies could be downloaded at faster rates, Rattner said.

Laser is already used in devices such as DVD players, and also for applications such as long-distance communication. Laser technology can however be expensive, and Intel wants to bring the technology down to a low-cost point where it can be integrated into everyday devices, Rattner said. The company hopes to raise the speed of the optical interconnect to reach up to 1T bps (bits per second) as it increases the number of channels to improve data transfers.

But for now, the company has demonstrated in principle that it can get the pieces together and put it together in a fab. The next step is to implement it in chips and take it to volume manufacturing. The technology could reach the mass market by the middle of the decade, and could go into PCs, servers or mobile devices.

The technology won’t be implemented at the integrated circuit level in the short term, but could replace copper wires that connect CPU to memory, for example, said Mario Paniccia, an Intel fellow. The optical interconnect will reduce latency, which could result in faster data movement and processing.

“We think it’s going to be perfectly at home in data-center applications,” Rattner said. For consumer applications, an optical interconnect would also help users to down movies to handheld devices at faster rates, Rattner said.

“Once we’re confident we have a high-volume manufacturing capability, then we’ll turn to the business question: what market opportunities are attractive to Intel?” Rattner asked.

The research prototype brings together a number of previous Intel research around devices that emit, manipulate, combine, separate and detect light. The interconnect includes a transmitter chip on a PC board that puts four optical channels on to fiber, and a receiver chip that receives the incoming light, splits the optical signals and converts the photons to electrical data.

Intel is already working on a new optical interconnect to link external storage drives, mobile devices and displays to PCs up to 100 meters away. Called Light Peak, the interconnect helps communicate data at up to 10G bps. Intel sees Light Peak as potential technology to replace USB, which is commonly used to connect storage and other devices to PCs.

Many companies, including Sun, which is now part of Oracle, and IBM have been involved in silicon photonics research.

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Native-Like Spider Silk Produced in

Metabolically Engineered Bacteria

Science (July 27, 2010) — Researchers have long envied spiders’ ability to manufacture silk that is light-weighted while as strong and tough as steel or Kevlar. Indeed, finer than human hair, five times stronger by weight than steel, and three times tougher than the top quality man-made fiber Kevlar, spider dragline silk is an ideal material for numerous applications. Suggested industrial applications have ranged from parachute cords and protective clothing to composite materials in aircrafts. Also, many biomedical applications are envisioned due to its biocompatibility and biodegradability.

Unfortunately, natural dragline silk cannot be conveniently obtained by farming spiders because they are highly territorial and aggressive. To develop a more sustainable process, can scientists mass-produce artificial silk while maintaining the amazing properties of native silk? That is something Sang Yup Lee at the Korea Advanced Institute of Science and Technology (KAIST) in Daejeon, the Republic of Korea, and his collaborators, Professor Young Hwan Park at Seoul National University and Professor David Kaplan at Tufts University, wanted to figure out. Their method is very similar to what spiders essentially do: first, expression of recombinant silk proteins; second, making the soluble silk proteins into water-insoluble fibers through spinning.

For the successful expression of high molecular weight spider silk protein, Professor Lee and his colleagues pieced together the silk gene from chemically synthesized oligonucleotides, and then inserted it into the expression host (in this case, an industrially safe bacterium Escherichia coli which is normally found in our gut). Initially, the bacterium refused to the challenging task of producing high molecular weight spider silk protein due to the unique characteristics of the protein, such as extremely large size, repetitive nature of the protein structure, and biased abundance of a particular amino acid glycine. “To make E. coli synthesize this ultra high molecular weight (as big as 285 kilodalton) spider silk protein having highly repetitive amino acid sequence, we helped E. coli overcome the difficulties by systems metabolic engineering,” says Sang Yup Lee, Distinguished Professor of KAIST, who led this project. His team boosted the pool of glycyl-tRNA, the major building block of spider silk protein synthesis. “We could obtain appreciable expression of the 285 kilodalton spider silk protein, which is the largest recombinant silk protein ever produced in E. coli. That was really incredible.” says Dr. Xia.

But this was only step one. The KAIST team performed high-cell-density cultures for mass production of the recombinant spider silk protein. Then, the team developed a simple, easy to scale-up purification process for the recombinant spider silk protein. The purified spider silk protein could be spun into beautiful silk fiber. To study the mechanical properties of the artificial spider silk, the researchers determined tenacity, elongation, and Young’s modulus, the three critical mechanical parameters that represent a fiber’s strength, extensibility, and stiffness. Importantly, the artificial fiber displayed the tenacity, elongation, and Young’s modulus of 508 MPa, 15%, and 21 GPa, respectively, which are comparable to those of the native spider silk.

“We have offered an overall platform for mass production of native-like spider dragline silk. This platform would enable us to have broader industrial and biomedical applications for spider silk. Moreover, many other silk-like biomaterials such as elastin, collagen, byssus, resilin, and other repetitive proteins have similar features to spider silk protein. Thus, our platform should also be useful for their efficient bio-based production and applications,” concludes Professor Lee.

This work is published on July 26 in the Proceedings of the National Academy of Sciences (PNAS) online

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Plastic Antibody Works in First Tests

in Living Animals

Science (June 11, 2010) — Scientists are reporting the first evidence that a plastic antibody — an artificial version of the proteins produced by the body’s immune system to recognize and fight infections and foreign substances — works in the bloodstream of a living animal.

The discovery, they suggest in a report in the Journal of the American Chemical Society, is an advance toward medical use of simple plastic particles custom tailored to fight an array of troublesome “antigens.”

Those antigens include everything from disease-causing viruses and bacteria to the troublesome proteins that cause allergic reactions to plant pollen, house dust, certain foods, poison ivy, bee stings and other substances.

In the report, Kenneth Shea, Yu Hosino, and colleagues refer to previous research in which they developed a method for making plastic nanoparticles, barely 1/50,000th the width of a human hair, that mimic natural antibodies in their ability to latch onto an antigen. That antigen was melittin, the main toxin in bee venom. They make the antibody with molecular imprinting, a process similar to leaving a footprint in wet concrete. The scientists mixed melittin with small molecules called monomers, and then started a chemical reaction that links those building blocks into long chains, and makes them solidify. When the plastic dots hardened, the researchers leached the poison out. That left the nanoparticles with tiny toxin-shaped craters.

Their new research, together with Naoto Oku’s group of the University Shizuoka Japan, established that the plastic melittin antibodies worked like natural antibodies. The scientists gave lab mice lethal injections of melittin, which breaks open and kills cells. Animals that then immediately received an injection of the melittin-targeting plastic antibody showed a significantly higher survival rate than those that did not receive the nanoparticles. Such nanoparticles could be fabricated for a variety of targets, Shea says. “This opens the door to serious consideration for these nanoparticles in all applications where antibodies are used,” he adds.

Sourced and published by Henry Sapiecha 12th June 2010

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EcoWire™: A True Engineering Breakthrough
Tough wire doesn’t have to be bulky or hard to recycle. Innovative EcoWire combines increased performance with a minimized environmental impact. EcoWire’s unique mPPE insulation is inherently lighter, tougher, and more durable than PVC. Plus, it contains no halogens and meets WEEE requirements.

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Sourced and published by Henry Sapiecha 5th June 2010

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