Plastic that heals itself

Monday, June 11, 2007

Developed a new material that can fill in its own surface cracks.

Self-healer: Modeled on human skin, a new material that heals itself multiple times is made of two layers. The polymer coating on top contains tiny catalyst pieces scattered throughout. The substrate contains a network of microchannels carrying a liquid healing agent. When the coating cracks, the cracks spread downward and reach the underlying channels, which ooze out healing agent. The agent mixes with the catalyst and forms a polymer, filling in the cracks.

Researchers at the University of Illinois at Urbana-Champaign (UIUC) have made a polymer material that can heal itself repeatedly when it cracks. It's a significant advance toward self-healing medical implants and self-repairing materials for use in airplanes and spacecraft. It could also be used for cooling microprocessors and electronic circuits, and it could pave the way toward plastic coatings that regenerate themselves.

The first self-healing material was reported by the UIUC researchers six years ago, and other research groups have created different versions of such materials since then, including polymers that mend themselves repeatedly when subject to heat or pressure. But this is the first time anyone has made a material that can repair itself multiple times without any external intervention, says Nancy Sottons, materials-science and engineering professor at UIUC and one of the researchers who led the work.

"It's essentially like giving life to a plastic," says Chris Bielawski , a chemistry professor at the University of Texas at Austin. The ultimate goal would be to create materials that mend themselves, he says, and "this is an amazing proof of concept."

Sottos and her colleagues have designed the new material, reported in this week's Nature Materials, to mimic human skin. If the skin's outer protective layer is cut, the inner layer, which is infused with a dense network of tiny blood vessels, rushes nutrients to the cut to help with healing. The self-healing material consists of an epoxy polymer layer deposited on a substrate that contains a three-dimensional network of microchannels. The epoxy coating contains tiny catalyst particles, while the channels in the substrate are filled with a liquid healing agent.

To test the material, the researchers bend it and crack the polymer coating. The crack spreads down through the coating and reaches the underlying microchannel. This prompts the healing agent to "whip through the channels and into the crack," Sottos says. There, it comes into contact with the catalyst and, in about 10 hours, becomes a polymer and fills in the crack. The system does not need any external pressure to push the healing agent into the crack. Instead, the liquid moves through the narrow channels just as water moves up a straw.

The researchers are able to crack and reheal the surface as many as seven times before the catalyst wears out and stops working. The next generation of the self-healing material should be able to heal itself many more times, according to the researchers. Sottos and her colleagues are designing it so that it will have a two-part system that injects both a healing agent and a catalyst into the crack.

The researchers could also increase the rehealing capacity of the material by hooking up the microchannel network to a little reservoir, Sottos says. If the material runs out of healing agent or catalyst, the reservoir could pump in more.

The material's microchannel design could be a solution to the increasing problem of heat buildup in microelectronics chips. Typically, microelectronic circuit chips sit on substrates that are designed to conduct heat away from the circuit. These heat regulators have their limits. Instead, Sottos says, "you could put a cooling fluid through a [microchannel] network like a little mini-heat exchanger."

Sottos says that researchers could use the same design with other resin and catalyst combinations that can form different polymers. This opens the door for many other applications. While practical self-healing materials might be years away, it's easy to imagine their applications in prosthetics and medical implants made from biocompatible self-healing materials. The cost of the materials might keep them limited, at least initially, to certain high-value, high-performance applications such as use in air- and spacecraft, says Ian Bond , aerospace engineering professor at the University of Bristol, in the United Kingdom.

In the future, different chemistries could lead to cheaper self-healing materials, according to Bielawski. "You could use cheap epoxies ... that you can buy at Home Depot ... as a healing agent," he says.

Credit: J. Hanlon, Univ. of Illinois Beckman Institute

source: Technology Review

Wireless Electricity (Witricity)

7 June 2007, Massachusetts Institute of Technology (MIT),
Institute for Soldier Nanotechnologies,


Imagine a future in which wireless power transfer is feasible: cell phones, household robots, mp3 players, laptop computers and other portable electronics capable of charging themselves without ever being plugged in, freeing us from that final, ubiquitous power wire. Some of these devices might not even need their bulky batteries to operate.

Realizing their recent theoretical prediction, they were able to light a 60W light bulb from a power source seven feet (more than two meters) away; there was no physical connection between the source and the appliance. The MIT team refers to its concept as "WiTricity" (as in wireless electricity). The work will be reported in the June 7 issue of Science Express, the advance online publication of the journal.

The key: Magnetically coupled resonance

WiTricity is based on using coupled resonant objects. Two resonant objects of the same resonant frequency tend to exchange energy efficiently, while interacting weakly with extraneous off-resonant objects. A child on a swing is a good example of this. A swing is a type of mechanical resonance, so only when the child pumps her legs at the natural frequency of the swing is she able to impart substantial energy.

Another example involves acoustic resonances: Imagine a room with 100 identical wine glasses, each filled with wine up to a different level, so they all have different resonant frequencies. If an opera singer sings a sufficiently loud single note inside the room, a glass of the corresponding frequency might accumulate sufficient energy to even explode, while not influencing the other glasses. In any system of coupled resonators there often exists a so-called "strongly coupled" regime of operation.

While these considerations are universal, applying to all kinds of resonances (e.g., acoustic, mechanical, electromagnetic, etc.), the MIT team focused on one particular type: magnetically coupled resonators. The team explored a system of two electromagnetic resonators coupled mostly through their magnetic fields; they were able to identify the strongly coupled regime in this system, even when the distance between them was several times larger than the sizes of the resonant objects. This way, efficient power transfer was enabled.

Magnetic coupling is particularly suitable for everyday applications because most common materials interact only very weakly with magnetic fields, so interactions with extraneous environmental objects are suppressed even further. "The fact that magnetic fields interact so weakly with biological organisms is also important for safety considerations," Kurs, a graduate student in physics, points out.

The investigated design consists of two copper coils, each a self-resonant system. One of the coils, attached to the power source, is the sending unit. Instead of irradiating the environment with electromagnetic waves, it fills the space around it with a non-radiative magnetic field oscillating at MHz frequencies. The non-radiative field mediates the power exchange with the other coil (the receiving unit), which is specially designed to resonate with the field. The resonant nature of the process ensures the strong interaction between the sending unit and the receiving unit, while the interaction with the rest of the environment is weak.

Moffatt, an MIT undergraduate in physics, explains: "The crucial advantage of using the non-radiative field lies in the fact that most of the power not picked up by the receiving coil remains bound to the vicinity of the sending unit, instead of being radiated into the environment and lost." With such a design, power transfer has a limited range, and the range would be shorter for smaller-size receivers.

Source: (MIT News)

Other articles about it:

Selfserviceworld.com
eurekalert.org

Video:


BBC Special (youtube)

Telepathic Remote

HATOYAMA, Japan,2007

Brain-machine interface developed by HITACHI.

Forget the clicker: A new technology in Japan could let you control electronic devices without lifting a finger simply by reading brain activity.

A cap connects by optical fibers to a mapping device, which links, in turn, to a toy train set via a control computer and motor during one recent demonstration at Hitachi's Advanced Research Laboratory in Hatoyama, just outside Tokyo.

"Take a deep breath and relax," said Kei Utsugi, a researcher, while demonstrating the device on Wednesday.

At his prompting, a reporter did simple calculations in her head, and the train sprang forward — apparently indicating activity in the brain's frontal cortex, which handles problem solving.
Activating that region of the brain — by doing sums or singing a song — is what makes the train run, according to Utsugi. When one stops the calculations, the train stops, too.
Underlying Hitachi's brain-machine interface is a technology called optical topography, which sends a small amount of infrared light through the brain's surface to map out changes in blood flow.

Although brain-machine interface technology has traditionally focused on medical uses, makers like Hitachi and Japanese automaker Honda Motor Co. have been racing to refine the technology for commercial application.
Hitachi's scientists are set to develop a brain TV remote controller letting users turn a TV on and off or switch channels by only thinking.
Honda, whose interface monitors the brain with an MRI machine like those used in hospitals, is keen to apply the interface to intelligent, next-generation automobiles.
The technology could one day replace remote controls and keyboards and perhaps help disabled people operate electric wheelchairs, beds or artificial limbs.
Initial uses would be helping people with paralyzing diseases communicate even after they have lost all control of their muscles.

Since 2005, Hitachi has sold a device based on optical topography that monitors brain activity in paralyzed patients so they can answer simple questions — for example, by doing mental calculations to indicate "yes" or thinking of nothing in particular to indicate "no."
"We are thinking of various kinds of applications," project leader Hideaki Koizumi said. "Locked-in patients can speak to other people by using this kind of brain machine interface."
A key advantage to Hitachi's technology is that sensors don't have to physically enter the brain. Earlier technologies developed by U.S. companies like Neural Signals Inc. required implanting a chip under the skull.

Still, major stumbling blocks remain.
Size is one issue, though Hitachi has developed a prototype compact headband and mapping machine that together weigh only about two pounds.
Another would be to tweak the interface to more accurately pick up on the correct signals while ignoring background brain activity.
Any brain-machine interface device for widespread use would be "a little further down the road," Koizumi said.
He added, however, that the technology is entertaining in itself and could easily be applied to toys.
"It's really fun to move a model train just by thinking," he said.






source: By HIROKO TABUCHI, Associated Press Writer Fri Jun 22, 3:01 PM ET, '07

Flexible Video (e-paper)

First A4 Color e-paper

Seoul, Korea (May 13, 2007)

LG.Philips,

a leading innovator of thin-film transistor liquid crystal display (TFT-LCD) technology, announced today that it developed the world’s first 14.1-inch flexible color E-paper display, equivalent in size to an A4 sheet of paper. This is a second breakthrough in E-paper for LG.Philips LCD, which introduced the world’s first 14.1-inch black and white flexible E-paper display in May 2006.

The 14.1-inch flexible color E-paper uses electronic ink from E-Ink Corp. to produce a maximum of 4,096 colors. It can be viewed from a full 180 degrees, so that images always appear crisp, even when the display is bent.
Like the black and white flexible display, the color version uses a substrate that arranges Thin-Film Transistors (TFT) on metal foil rather than glass, allowing it to recover its original shape after being bent. This model includes a color filter coated onto the plastic substrate, allowing it to display color images.

LG.Philips LCD’s use of metal foil and plastic substrate rather than glass substrate makes the flexible color E-paper display bendable and durable while maintaining excellent display qualities.

To make this new display possible the company developed proprietary processing technology that minimizes panel deformation and prevents circuit structure change during high-temperature processes. LG.Philips LCD focused on the designs of the color filter structure and TFT, as well as color filter lamination technology. This allowed them to overcome processing difficulties inherent in the lack of heat resistance in metal foil and plastic substrates.

These displays are extremely energy efficient, only using power when the image changes. Additionally the displays are extremely thin, less than 300 micrometers(㎛). The images displayed are comparable in quality to printed pages.


In October 2005 LG.Philips LCD unveiled the world’s first 10.1-inch flexible E-paper display. The company followed it up with its groundbreaking 14.1-inch model in May 2006.

Flexible Display Market Projection
According to a recent report from Displaybank, a Korea-based research firm specializing in the display industry, the flexible display market is projected to grow into a USD 5.9 billion market by 2010, rising to USD 12 billion by 2015.

Video:

Comparison LCD vs E-PAPER

(Source: LG-Philipps website)

3D Poster

XYZ Imaging Inc.,

is the world’s first holographic printing bureau capable of creating production ready multi-resolution, full color, reflective holograms from pure digital media.

This technology uses patented holographic technology developed over a 6 year timeframe at a cost of nearly $ 23 Million US dollars. Combined with a revolutionary emulsion that is more than 300 times finer than ISO 300 film on a super wide format that measures over 1 m wide, allowing for the
production of never-before-seen large format holographic prints with a single sheet size of: 1m wide x 1.2m long or longer (based on the length of the film roll).

What is a hologram? A hologram is a three-dimensional scene with an incredible illusion of depth and motion that is unlike anything you've seen before. These holograms can be appreciated without glasses or a special viewing device. XYZ Imaging has created a new breed of large format, color static (non-rainbow) reflective holograms that astound viewers, gathers crowds and becomes the hot topic of conversation wherever they are displayed.

www.xyzimaging.com
PDF

Video:

Light-emitting textiles

(Lumalive)-Philips


(click to see the video)

Behind the outer fabric,
you will find a layered system containing flexible arrays of colored light-emitting diodes (LEDs), only visible from the outside when the display panel is switched on. The system is modular and can be removed easily when you want to wash your garments or clean your soft furnishings.

Lumalive textiles bring inert objects to life by integrating flexible arrays of multi-colored light-emitting diodes (LEDs) into fabrics without compromising the softness of the cloth. The integration of electronic lighting devices into textiles is groundbreaking. Clothing, towels, upholstery, and drapes might at first seem unlikely hosts for intelligent and interactive systems, yet they figure prominently in our lives and as such present a wide spectrum of opportunity.


What is the technology behind Lumalive?
Lumalive fabrics feature Philips’ proprietary technology of integrating flexible arrays of light-emitting diodes (LEDs) into the fabric. The integrated control unit makes it possible to change the light patterns and to show full color animations. The control unit is programmable. The system obtains its power from a small battery pack or the mains.

What part of this technology is unique to Philips?
High level of fabric integration of LED technology. Our proprietary technology allows us to easily implement light emitting fabrics in concrete applications.

Has Lumalive been trademarked?
Lumalive is a trademark of Royal Philips Electronics. The Photonic Textiles business unit is a corporate venture within Royal Philips. Royal Philips Electronics of the Netherlands is a global leader in healthcare, lifestyle and technology, delivering products, services and solutions through the brand promise of “sense and simplicity”. By developing technologies not for technology’s sake, we create products that enhance people’s lives in a meaningful way.

When will Lumalive be available in the market?
The commercial launch of the first Lumalive application is expected by the end of 2007. The products will be commercially available via selected partners in the promotion & event industry.


General technical information

Power consumption
The electronics and batteries to power a Lumalive system are not visible in the application and require very little power. The rechargeable battery runs for 3 to 4 hours on one charge.

Removable for washing
The Lumalive panel is splash-resistant. Furthermore, the whole system, including batteries and electronics, is modular, and easily removable when you want to wash the clothing or fabric.

Display panel sizes
The standard Lumalive panel is based on 14x14 RGB LEDs.

The amount of colors
The Lumalive panel can produce 16 million individual colors.

Display brightness. Can it be used in broad daylight?
The brightness of the panel depends on the LEDs used. The standard panel is designed for low to medium ambient lighting conditions.


(source: Philips site "Lumalive" 2007)

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