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Research into color-changing nanoparticles could pave the way for a new kind of display technology. A breakthrough promises tiny molecules that can change color in response to an external magnetic field that can be used to create outdoor displays and posters.

“We have developed a new way to induce color change in materials that can be fabricated on a large scale and is pretty close to commercialization,” says Yadong Yin, an assistant professor of chemistry at University of California, Riverside, who led the study that included contributions from South Korean scientists.

The technique centers on polymer beads, called magnetochromatic microspheres, which are dispersed in a liquid such as water, alcohol or hexane.

Inside the beads are magnetic iron oxide nanostructures. Changing the orientation of the nanostructures with an external magnetic field helps produce the change in color of the beads.

The process is similar to the way electrophoretic displays, more commonly known as electronic ink, work. The two systems share common properties such as being bistable (stable in two distinct states), being readable in direct sunlight and consuming very little power.

To fabricate the polymer beads or microspheres, researchers mixed magnetic iron oxide particles into a resin. The resin solution was then dispersed in either mineral oil or silicon oil, which transformed the resin into spherical droplets in the oil. An external magnetic field organizes the iron oxide particles into periodically ordered chains that display a reflective color if viewed along the direction of the magnetic field.

“For instance, in a vertical field, the particle chains stand straight so that their diffraction is turned ‘on’ and and corresponding color can be observed from
the top,” say the researchers in their study.  When the field is switched horizontally, the microspheres are forced to rotate 90 degrees to lay down the particle chains so that the diffraction is turned off. The microspheres then
show the native brown color of iron oxide.  Depending on the direction of the external magnetic field there can also be intermediate stages.

As the final step, the liquid system which holds the particles is exposed to ultraviolet radiation to polymerize the resin droplets and make them into solid microspheres. This allows for switching between two states. The solid state allows for the color information to be frozen and retained for long times without the  need for additional power.

Yin did not explain exactly how many colors can be obtained from the display but said the system can handle a reasonably wide range, though switching to colors at the opposite ends of the spectrum could be a challenge.

The researchers published the result of their study in the latest issue of the Journal of the American Chemical Society.

Yin sees applications such large outdoor displays that can be expensive to do with LCDs or other display technologies. “If you want a huge LCD display outside the house it can be uneconomical,” he says. “We can do it for much cheaper with this new technology.”

The displays are reflective, so they can offer high visibility even in strong sunshine, says Yin. The new material also can be used to make environmentally friendly pigments for paints and cosmetics.

Here’s a quick video that shows the rotation of the microspheres in a vertically changing external magnetic field. The color is switched between on (blue) and off states.

Photo: Colorful microspheres/University of California, Riverside

Our very own Josh Topolsky will once again be invading America’s airwaves tonight from the set of Late Night with Jimmy Fallon, and you know he’ll be showing off another hot new toy. (What could it be?) Tune in on your local NBC station at the times listed below, let us know how he’s doing in comments, and make sure to include #joshtops in your tweets!

Oh, and if you missed JT and Jimmy get silly with the Pre back in March (or you just want to relive it), the video’s after the break.

Showtimes:
12:37AM Eastern
11:37PM Central
11:37PM Mountain
12:37AM Pacific

Continue reading Josh is on Late Night with Jimmy Fallon tonight!

Filed under: Misc. Gadgets

Josh is on Late Night with Jimmy Fallon tonight! originally appeared on Engadget on Wed, 17 Jun 2009 15:07:00 EST. Please see our terms for use of feeds.

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Power users running low on desktop space now have some breathing room with the introduction of AVADirect.com and GTR Tech‘s small form factor GT3 case. Despite its smaller size, the case uses the full ATX form factor, ensuring compatibility with a majority of motherboards and components. The case will take up only 25% of the footprint of mid-tower computer cases and will be substantially easier to transport, AVADirect.com said. In addition, the company will be selling full systems based on the new case, as well as the case itself, on their website.

Though the GT3 might be the first full ATX case in a small form factor, Falcon Northwest also offers a small, turbo-charged gaming PC running in a microATX case. Those looking for the smallest case regardless of price would do well to take a look at Falcon’s offering, but if you just want something smaller than you’re used to without sacrificing compatibility, the GT3 might be the best choice. For gamers looking for a little bit more space and portability, the GT3 is available for your next LAN party for $179.20 (chassis only).

If it ain’t broke, don’t fix it — right? We know countless reviews of the iPhone 3G S may begin with that cliché, but there’s little chance you’d find a better way to describe the strategy that Apple has just put into play with its latest smartphone. In many ways, the 3G S is a mirror image of the iPhone 3G; externally there’s no difference. It’s inside where all the changes have happened, with Apple issuing a beefed-up CPU, new internal compass, larger capacities for storage, and improved optics for its camera. More to the point, the release of the 3G S coincides with the launch of iPhone OS 3.0, a major jump from previous versions of the system software featuring highly sought after features like cut, copy, and paste, stereo Bluetooth, MMS, tethering, video recording, landscape keyboard options for more applications, and an iPhone version of Spotlight. At a glance, what Apple seems to be doing is less a reinvention of the wheel and more like retreading the wheel it’s already got (and what a wheel, right?). So, do the iPhone 3G S and OS 3.0 tweak the details in just the right places, or has Apple gone and gotten lazy on us? Read on to find out.

Continue reading iPhone 3G S review

Filed under: Cellphones

iPhone 3G S review originally appeared on Engadget on Wed, 17 Jun 2009 14:14:00 EST. Please see our terms for use of feeds.

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We’ve spent some quality time with the iPhone 3GS over the last couple of days and it looks like Apple is going to remain king of the smartphones with its latest iDevice. Although the 3GS is not significantly changed from the older 3G model, there are still a number of updates that make the 3GS noteworthy. From the mind of reviewer Steven Levy:

It’s not as dramatic an advance as the previous ones. But the new phone introduces a long list of improvements, big and small. Taken together, they’re enough to re-establish Apple’s once-shrinking lead in a brutal technology competition that is making the chariot race in Ben Hur look like a walk in the park.

As promised, Apple has indeed ramped up the speed with which the new phone performs tasks like launching apps, loading web pages, and displaying graphics. Apple claims speed boosts of up to two times of what the 3G delivers, and in some benchmarks cites even better performance. I haven’t done scientific measurements, but you don’t need a stopwatch to notice the new phone is zippier than its predecessor. I appreciated getting box scores faster and videos playing sooner in the MLB.com At Bat application, and it was clear that web pages loaded faster. In the case of a game like Tiger Woods Golf, the boost is significant enough to make me more likely to play when I don’t have much time.

In part because Apple is offering many of its innovations as part of the general iPhone 3.0 upgrade — the wise thing for those more recent buyers to do will be to install the new software and stick with their 3G iPhones at least until their contracts run down. This will provide a saner upgrade path to the 3GS’s considerable, but not earth-shattering, improvements. Speed is wonderful. But sometimes it’s prudent to wait for it.

Remember, this isn’t the whole review — just a mere sampling to get your motor running. For the deeper download hit up wired.com/reviews or click here for the full version.