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John Rogers, left, and Theodore Zoli.

The names of the 2009 John D. and Catherine T. MacArthur Foundation Fellows (the “genius” awards) were announced today, and I want to draw attention to two of the people on the list who are deep in new materials, John Rogers and Ted Zoli.

Rogers, whom I first wrote about last October, is a professor of materials science and engineering at the University of Illinois at Urbana-Champaign, has been involved in the development of a new form of flexible, stretchable silicon integrated circuit that can wrap around complex shapes, but they can do so without sacrificing electrical performance while stretching, compressing and folding is taking place. Rogers has also used carbon nanotubes to achieve similar results.

In regard to Rogers’ work, the foundation noted:

Such devices can be placed in locations where standard silicon wafer technologies are impractical or impossible; the myriad of potential applications include photovoltaic cells, adaptive optics, electronic textiles, and implantable biomimetic circuits. Through his basic research in nanotechnology, chemical engineering, and applied physics, Rogers is building the foundation for a revolution in manufacture of industrial, consumer, and biocompatible electronics.

Zoli is a structural engineer who is vice president and technical director of bridges with HNTB Corporation. He is also an instructor in civil engineering at Princeton and Columbia Universities.

The foundation praised Zoli’s design aesthetics (”elegant and enduring bridges around the world”) and his technical contributions “to protect transportation infrastructure in the event of natural and man-made disasters:”

Drawing from military research on terrorist weapon technologies and tank armor, he developed a novel composite material that represents the state of the art in lightweight, blast-resistant coverings for a broad array of construction applications. In an era of aging infrastructure and catastrophic structural collapses, Zoli is safeguarding vulnerable links in the nation’s highway system and developing design principles for the construction of robust, new landmarks in the United States and across the globe.

I haven’t been able to find out a whole lot about Zoli’s blast-resistant material, but this release suggests that he has been working with Hardwire Composite Armor Systems, a firm that has several lines of products for use in bridges, construction and military applications.

Congratulations to Rogers, Zoli and the rest of the new MacArthur Fellows.

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This is a brief video. Maybe I am overwhelmed by this because of my chemistry background, but in my opinion, this video documents what truly should be “wow”-level historical type of moment in material-related sciences. As the folks at the Lawrence Berkeley Nation Lab note, this is equivalent to the first biologist who peered through a microscope and saw a cell divide.

To summarize, this video is no more, or less, than watching for the first time, in real-time, individual carbon atoms being knocked off the edges of a hole in a sheet of graphene while other atoms break and recreate bonds as they shift around in response, looking for the most stable position. The video also contains a simulation of what is occurring (created using a Monte Carlo simulation method to “orchestrate” which carbon atoms leave and which shift).

And, like all really great movies, it’s hard to tell who deserves more credit: The actors or the director and cinematographers? The analogy isn’t perfect, but as awesome as this movie is, what is equally amazing is the incredible electron microscope behind the movie - TEAM 0.5.

TEAM 0.5, which just recently became operational, is the world’s most powerful electron microscopy. The technology behind TEAM 0.5 come from a team that includes the Berkeley, Argonne and Oak Ridge National Labs, the Frederick Seitz Materials Lab of the University of Illinois, and two electron microscopy companies, FEI (Portland) and CEOS of (Heidelberg).

In some ways, researchers are just starting to “play” with TEAM and are already planning on using it on other structures and materials. Nevertheless, this first video is providing new leads and confirmations to those studying spin properties in atoms.

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Circuit diagram (top frame) and optical images of a stretchable, "wavy" silicon ring oscillator circuit on a rubber substrate, in the "as fabricated" flat state (top micrograph) and in moderate and high states of biaxial compression (middle and bottom micrographs, respectively). Credit: Rogers.

Researchers led by John Rogers, a professor of materials science and engineering at the University of Illinois at Urbana-Champaign, have developed a new form of flexible, stretchable silicon integrated circuit. Not only can these new silicon circuits wrap around complex shapes, but they can do so without sacrificing electrical performance while stretching, compressing and folding is taking place, the researchers say. “The notion that silicon cannot be used in such applications because it is intrinsically brittle and rigid has been tossed out the window,” says Rogers, whose findings have been published in Science Magazine and posted on its  ScienceXpress website.”Through carefully optimized mechanical layouts and structural configurations, we can now use silicon in integrated circuits that are fully foldable and stretchable,” Rogers says. The development could lead to new types of sensors that can be integrated into artificial muscles, wearable health-monitoring systems or electrical devices that can wrap around aircraft wings and fuselages to monitor structural properties.

‘Wavy’ electronics

Rogers and his UI research team had previously reported the development of a one-dimensional, stretchable form of single-crystal silicon with micron-sized, wave-like geometries in 2005. He said then that the configuration allowed reversible stretching in one direction without significantly altering electrical properties, but only at the level of individual material elements and devices. Now Rogers and collaborators at the UI, Northwestern University, and the Institute of High Performance Computing in Singapore are reporting the extension of this earlier “wavy” development to two dimensions capable of yielding functional integrated circuit systems. Rogers reports constructing integrated circuits consisting of transistors, oscillators, logic gates and amplifiers and notes that these circuits exhibited extreme levels of bendability and stretchability, demonstrating electronic properties comparable to those of similar circuits built on conventional silicon wafers. “We’ve gone way beyond just isolated material elements and individual devices to complete, fully integrated circuits in a manner that is applicable to systems with nearly arbitrary levels of complexity,” Rogers says.

Methodology

To create fully stretchable integrated circuits, the researchers apply a sacrificial layer of polymer to a rigid carrier substrate, Rogers says. On top of the sacrificial layer, they deposit a very thin plastic coating that supported the integrated circuit. He notes that the circuit components are then crafted using conventional techniques for planar-device fabrication, along with printing methods for integrating aligned arrays of nanoribbons of single-crystal silicon. The researchers’ next step, according to Rogers, is to wash away the sacrificial polymer layer and bond the plastic coating and integrated circuit to a piece of pre-strained silicone rubber. Lastly, he says, they relieve the strain and - as the rubber springs back to its initial shape - apply compressive stresses to the circuit sheet. These stresses spontaneously lead to a complex pattern of buckling, creating a geometry that then allowed the circuit to be folded or stretched in different directions, giving it the ability to conform to complex shapes or to accommodate to the mechanical deformations that occur during use. “The wavy concept now incorporates optimized mechanical designs and diverse sets of materials, all integrated together in systems that involve spatially varying thicknesses and material types,” he explains, adding that the “overall buckling process yields wavy shapes that vary from place to place on the integrated circuit, in a complex but theoretically predictable fashion.”

Rogers stresses that attaining high degrees of mechanical flexibility or foldability is important to sustaining the wavy shapes. “The more robust the circuits are under bending, the more easily they will adopt the wavy shapes which, in turn, allow overall system stretchability,” he says. “For this purpose, we use ultra thin circuit sheets designed to locate the most fragile materials in a neutral plane, minimizing their exposure to mechanical strains during bending.” “We’re opening an engineering design space for electronics and optoelectronics that goes well beyond what planar configurations on semiconductor wafers can offer,” Rogers states, indicating that NSF and DOE are funding his research.

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