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Bio for nano: Engineers work to create new biomaterials with energy technology applications

University of Delaware materials science professors Darrin Pochan and Kristi Kiick are taking a new approach to building new nanomaterials from biomolecules—namely peptides and proteins—that could increase the efficiency of photovoltaics, and other electronic devices. “Peptides and polypeptides offer unlimited potential in designing new materials that can uniquely address limitations in current electronic devices,” Kiick notes. This is because proteins can be engineered to display chemically reactive groups at desired positions. By constructing a nanomaterial with proteins, researchers can subsequently add inorganic nanoparticles that will “stick” to the nanomaterial surface in targeted locations. If successful, Pochan says the project could offer manufacturers a “dirt simple” processing and materials technique for creating a structured, protein-based backing that could be applied to photovoltaic devices to improve their efficiency. It may also create new opportunities to work with colleagues in energy disciplines - particularly those at UD - to test and refine the materials process. “Normal semiconductor manufacturing processes are extremely difficult and expensive at this small of a length scale, making this research area very important,” Pochan says.

Scientists create flexible mineral inspired by deep-sea sponges

Scientists at Johannes Gutenberg University Mainz (JGU) and the Max Planck Institute for Polymer Research (MPI-P) in Germany have created a new synthetic hybrid material with a mineral content of almost 90%, yet extremely flexible. They imitated the structural elements found in most sea sponges and recreated the sponge spicules using the natural mineral calcium carbonate and a protein of the sponge. Natural minerals are usually very hard and prickly, as fragile as porcelain. Amazingly, the synthetic spicules are superior to their natural counterparts in terms of flexibility, exhibiting a rubber-like flexibility. The synthetic spicules can, for example, easily be U-shaped without breaking or showing any signs of fracture. This highly unusual characteristic is mainly due to the part of organic substances in the new hybrid material. It is about ten times as much as in natural spicules. The synthetic spicules were made from calcite and silicatein-α. The synthetic material was self-assembled from an amorphous calcium carbonate intermediate and silicatein and subsequently aged to the final crystalline material. After six months, the synthetic spicules consisted of calcite nanocrystals aligned in a brick wall fashion with the protein embedded like cement in the boundaries between the calcite nanocrystals. The spicules were of 10 to 300 micrometers in length with a diameter of 5 to 10 micrometers.

Obama reiterates plan to use oil revenue for alternative energy R&D

(Oil & Gas Journal) Technological breakthroughs in the last few years have significantly improved the US energy situation, but more needs to be done, US President Barack Obama said on Mar. 15. He specifically called for creation of an Energy Security Trust to develop and deploy transportation alternatives that would be funded by federal crude oil leasing revenue. He acknowledged, as he did in his Feb. 12 State of the Union address, that the idea came from Securing America’s Future Energy (SAFE), which is committed to protecting US national and economic security by combating domestic dependence on oil for transportation fuels.

New electronic ‘tattoos’ could help monitor health during normal daily activities

(Technology Review) Taking advantage of recent advances in flexible electronics, researchers have devised a way to “print” devices directly onto the skin so people can wear them for an extended period while performing normal daily activities. Such systems could be used to track health and monitor healing near the skin’s surface, as in the case of surgical wounds. So-called “epidermal electronics” were demonstrated previously in research from the lab of John Rogers, a materials scientist at the University of Illinois at Urbana-Champaign; the devices consist of ultrathin electrodes, electronics, sensors, and wireless power and communication systems. In theory, they could attach to the skin and record and transmit electrophysiological measurements for medical purposes. These early versions of the technology, which were designed to be applied to a thin, soft elastomer backing, were “fine for an office environment,” says Rogers, “but if you wanted to go swimming or take a shower they weren’t able to hold up.” Now, Rogers and his coworkers have figured out how to print the electronics right on the skin, making the device more durable and rugged.

Observing titanium dioxide with ultrashort light pulses

When a crystal is hit by an intense ultrashort light pulse, its atomic structure is set in motion. A team of scientists from the Max Planck Institute of Quantum Optics, the Technischen Universität München (TUM), the Fritz-Haber Institute in Berlin (FHI) and the Universität Kassel can now observe how the configuration of electrons and atoms in titanium dioxide, a semiconductor, changes under the impact of an ultraviolet laser pulse, confirming that even subtle changes in the electron distribution caused by the excitation can have a considerable impact on the whole crystal structure. Knowledge regarding the interaction between light and solid matter on an atomic scale is still comparable to a map with many blank spots. A new, up to date unknown aspect of the interplay between light and matter has now been examined by a team of scientists using intensive ultraviolet laser pulses with only a few femtoseconds duration. The physicists illuminated a titanium dioxide crystal (consisting of titanium and oxygen atoms) with an intense ultraviolet laser pulse of less than five femtoseconds duration. The laser pulse excites the valence electrons in the crystal and generates a small number of hot electrons with a temperature of several thousand Kelvin. The continuous interplay between the positions of the atomic cores and the valence electrons determines the material characteristics such as electric conductivity, optical properties or the crystal lattice structure.

Device may lead to quicker, more efficient diagnostics

A twist on thin-film technology may provide a way to optically detect and analyze multiple substances simultaneously, leading to quicker diagnostics in such industries as health care and homeland security, according to Penn State researchers. One current optical-sensing technology can launch and guide a single light wave, called a surface-plasmon-polariton wave—SPP wave—that travels along the flat interface of the sample to be analyzed and a metal film. The SPP wave is launched by sending a light beam through a prism to the other face of the metal film. A photon detector eventually collects the beam that was reflected back into the prism. Any change in the optical properties of the sample critically alters the reflected beam. However, because the technology allows for only one SPP wave of a certain frequency to be guided through the device, the properties of only one substance can be analyzed for each sensor. The researchers designed a thin film that can create additional channels for the SPP waves. This thin film, which is attached to the metal surface, is porous and can be infiltrated by fluids that can later be analyzed. To make more channels for the SPP waves, they slowly rotated the substrate during the fabrication of the thin film, sculpturing it to create nanoscale springs, so that the regions between the springs can be infiltrated.

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Industrial scale solar installations need a lot of space and as much sunshine as possible.

We call such places deserts.

Unfortunately, though, most people find deserts unpleasant places to live.

One huge advantage of carbon-based energy sources is their transportability. Railroads and 18-wheelers constantly criss-cross the nation moving oil, natural gas, and coal from where they are plentiful (or processed) to where they are needed. One huge problem facing the hydrogen-based economy is that shipping the extremely light hydrogen is not practical.

Would it not be cool if solar energy could be trucked from the desert to somewhere it could be used—somewhere that people like to live and work? If you think about it, there is one resource that tends to be plentiful in areas where people do tend to settle and develop industry—water. Water, as I’ve mentioned before, is a great place to store hydrogen. Splitting the molecule apart is the tough part.

Getting these two energy resources together—sunshine and water—is the idea behind some new research coming out of the University of Delaware, where mechanical engineering professor Ajay Prasad and his group are making “solar fuel.”

This is not so much a materials engineering story as it is a materials exploitation story. Prasad and his graduate student, Erik Koepf, use basic thermodynamic principles to dissociate zinc oxide and precipitate zinc metal granules. Later, zinc metal is reacted with water, where it happily oxidizes and liberates hydrogen, which can be used as fuel.

Prasad said in a phone interview that he sees the technology as a way to “make zinc centrally, and then generate hydrogen locally.” He noted that a single tubular semi-truck can carry only about 100 kilograms of hydrogen, but can transport several tons of zinc particles.

It takes a lot of energy to dissociate zinc oxide, though, and Prasad’s and Koepf’s work focuses on designing a solar reactor that can concentrate enough sunlight and reach high enough temperatures to drive the dissociation reaction.

According to a press release, Koepf successfully tested a solar reactor design last April. Prasad told me, “We are at the proof-of-concept stage. In the first round of testing last April, we couldn’t get high enough temperatures. The reason is that the [reflector] mirror was too small, and we were losing available energy.” The reflector mirror directs the light from the solar concentrators into the reaction chambers.

During the April test, reactor temperatures of about 1,200 degrees Celsius were reached. Temperatures of about 1,400 to 1,700 degrees Celsius (1,700 to 2,000 K) are desired for the dissociation reaction. Since then, Koepf has been reworking the reactor design, especially the mirror component to focus 5,000 to 10,000 suns of concentrated energy into the reactor. When I talked to Prasad, Koepf was literally boarding a plane to test the tweaked solar reactor at the Solar Technology Laboratory at the Paul Scherrer Institute in Switzerland.

If you guessed that the reactor has ceramic components, you are correct. The reactor is a funnel-shaped design made of 15 fitted, trapezoid-shaped alumina plates. (A schematic diagram of one of the plates is shown above.). At the top of each trapezoid is a hopper of zinc oxide powder, which is sprinkled into the funnel with a metering spline. The powders descend through the reactor just by gravity.

According to a paper by Koepf, et al. published last fall in the International Journal of Hydrogen Energy, the first layer of powder sinters on top of the alumina plates, and subsequent layers of powders dissociate as they descend. The sintered zinc oxide layer does not react with the alumina and is easily scraped off. (Images from the paper, including the reactor, can be viewed without purchasing the paper.)

As shown in the diagram, there are three distinct temperature zones, each of which corresponds to different heat transfer mechanisms. Zone I is the preheat region with temperatures of 1,300-1,650 K. In Zone II, temperatures reach 1,650-1,800 K under diffuse radiation. The dissociation reaction begins here. Finally Zone III experiences direct radiation and temperatures in the 1,800-1,900 K range. Dissociation finishes here. At the bottom of the funnel, unreacted zinc oxide drops out. A flowing argon atmosphere helps create a tornado-like environment in the chamber, as well as sweeping the zinc vapor into an alumina collection tube. There, the vapor is quenched very quickly to condense it before reoxidation can occur. Overall, the powders spend about one-half second in the reactor.

The hydrolysis reaction to oxidize zinc happens at about 600 degrees Celsius. So, even though this is not an “energy cheap” process, it is passive and offers a mechanism for distributing energy resources. Prasad imagines an industrial-scale operation wherein a desert-based field of a thousand solar concentrator mirrors focus on a solar reactor mounted on a tower, and tons of dissociated zinc are trucked to sun-poor, water-rich areas where, by setting up favorable thermodynamics, hydrogen is generated.

His work is funded by the Department of Transportation, Federal Transit Administration.

The paper is, “A novel beam-down, gravity-fed, solar thermochemical receiver/reactor for direct solid particle decomposition: Design, modeling, and experimentation,” by Erik Koepf, Suresh G. Advani, Aldo Steinfeld, and Ajay K. Prasad; International Journal of Hydrogen Energy. DOI: 10.1016/j.ijhydene.2012.08.086.

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(Editor’s note: Eileen and I are traveling and preparing for the International Ceramics Congress that begins this weekend, so we had to put our normal writing on hold for a little bit. In place of our usual posts, we are bringing you a variety of good stories and videos issued prepared by various institutions. Look for our regular blog posts to return this weekend, including live blogging from ICC4.)

NIST Tech Beat - The National Institute of Standards and Technology is launching a new consortium that will take the measure of a growing and increasingly important class of materials-so-called soft materials. Soft materials is a huge field that ranges from products as commonplace as detergents, paints and chocolate bars to some as sophisticated as flexible electronic displays and solar cells, therapeutic drugs and plastics with tailor-made properties.

The kick-off meeting for the nSoft Consortium will be held Aug. 14, 2012, at the NIST main campus in Gaithersburg, Md. The new collaborative effort focuses on manufacturers of soft materials, including plastics, proteins, foods and composites. Member organizations will be able to leverage the capabilities and facilities of the NIST Center for Neutron Research and the expertise of NIST’s Material Measurement Laboratory, as well as the University of Delaware Center for Neutron Science.

Two key objectives of the effort are optimizing properties of selected soft materials and maximizing production yields. Beams of neutrons, which are uncharged particles in the nucleus of atoms, provide an unparalleled portal into the workings of materials. The NCNR’s specialized neutron-based equipment and measurement methods not only afford glimpses into the interior of soft materials, but they also can probe the movements of their molecular components.

“Over the last few decades, university, government, and a relative handful of industrial researchers have demonstrated the power of neutron probes in solving high-impact materials problems,” explains Ronald Jones, the NIST polymer scientist who is the director of nSoft. “We want to make measurement solutions based on neutrons more accessible to materials manufacturers and to help them develop internal expertise for exploiting these tools to address their own particular needs.”

Related to liquids and to rigid solids, but distinct from both, soft materials encompass polymers, glasses, complex fluids, gels, foams, proteins, DNA, membranes and many other natural and synthetic materials. Unifying characteristics are their complexity, a tendency to self-assemble, and the somewhat feeble bonds between their components. Because of these halfhearted internal linkages, soft materials are sensitive to changes in pressure and temperature.

Advances in nanotechnology create opportunities for new types of soft materials optimized for particular uses. Many of these customized materials are based on processing methods that result in internal molecular arrangements far from the material’s preferred state of equilibrium. According to a 2009 National Research Council report, manufacturing plants that make some types of these out-of-equilibrium materials may only operate at 50 to 60 percent of their design capacity.

“Small variations in processing parameters can drastically change material properties,” Jones says. “The need to precisely and accurately measure the response of soft materials to processing parameters increases as materials become more complex by design.”

On the basis of a planning workshop held last year and other outreach efforts, NIST expects industry interest in nSoft to be high. Academic and government research organizations also are welcome to join.

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Georgia Tech researchers pose with a computer model of graphene oxide’s structure and the chemical species that become part of it. Shown are (l-r, first row) Elisa Riedo and Suenne Kim, (l-r, second row) Angelo Bongiorno, Claire Berger and Si Zhou. Credit: Gary Meek, Georgia Tech.

Take a look:

Metastable material: Study shows availability of hydrogen controls chemical structure of graphene oxide

A new study shows that the availability of hydrogen plays a significant role in determining the chemical and structural makeup of graphene oxide. The study also found that after the material is produced, its structural and chemical properties continue to evolve for more than a month as a result of continuing chemical reactions with hydrogen. The Georgia Tech researchers began their studies with multilayer epitaxial graphene grown atop a silicon carbide wafer. Their samples included an average of ten layers of graphene. After oxidizing the thin films of graphene using the established Hummers method, the researchers examined their samples using XPS. Over about 35 days, they noticed the number of epoxide functional groups declining while the number of hydroxyl groups increased slightly. After about three months, the ratio of the two groups finally reached equilibrium. “We found that the material changed by itself at room temperature without any external stimulation,” said Suenne Kim, a postdoctoral fellow in Riedo’s laboratory. “The degree to which it was unstable at room temperature was surprising.”

Slip-and-slide power generators

Researchers from Vestfold University College in Norway have created a simple, efficient energy-harvesting device that uses the motion of a single droplet to generate electrical power. The new technology could be used as a power source for low-power portable devices, and would be especially suitable for harvesting energy from low frequency sources such as human body motion, write the authors in a paper accepted to the American Institute of Physics’ journal Applied Physics Letters. The harvester produces power when an electrically conductive droplet (mercury or an ionic liquid) slides along a thin microfabricated material called an electret film, which has a permanent electric charge built into it during deposition. Cyclic tilting of the device causes the droplet to accelerate across the film’s surface; the maximum output voltage (and power) occurs when the sliding droplet reaches its maximum velocity at one end of the film. A prototype of the fluidic energy harvester demonstrated a peak output power at 0.18 microwatts, using a single droplet 1.2 millimeters in diameter sliding along a 2-micrometer-thick electret film.

Reversible doping: Hydrogen flips switch on vanadium oxide

If vanadium oxide had its own TV infomercial, you’d already know: “It’s a metal. It’s an insulator. It’s a window coating and an optical switch.” And thanks to a new study by Rice University physicists - there’s more! The study shows how to reversibly alter VO₂′s quirky electronic properties by treating it with the simplest of substances-hydrogen. When oxygen reacts with vanadium to form VO₂, the atoms form crystals that look like long rectangular boxes. The vanadium atoms line up along the four edges of the box in regularly spaced rows. A single crystal of VO₂ can have many of these boxes lined up side by side, and the crystals conduct electricity like wire as long as they are kept warm. “The weird thing about this material is that if you cool it, when you get to 67°C, it goes through a phase transition that is both electronic and structural. When the phase changes, and these pairings take place, the material changes from being a electrical conductor to an electrical insulator,” says Rice’s Douglas Natelson, lead co-author of the study in this week’s Nature Nanotechnology. In 2010, Natelson and postdoctoral research associate Jiang Wei began to systematically study the phase changes in VO₂. Wei and graduate student Heng Ji began by using a process called vapor deposition to grow VO₂ wires that were about 1,000 times smaller than a human hair. One set of experiments on wires that had been baked in the presence of hydrogen gas returned particularly odd readings. Wei, Ji and Natelson determined that the hydrogen was apparently modifying the VO2 nanowires, but only those in contact with metal electrodes.

Utah-led group gets $15M from Army to design new materials

US soldiers are increasingly weighed down by batteries to power weapons, detection devices and communications equipment. So the Army Research Laboratory has awarded a University of Utah-led consortium almost $15 million to use computer simulations to help design materials for lighter-weight, energy efficient devices and batteries. “We want to help the Army make advances in fundamental research that will lead to better materials to help our soldiers in the field,” says computing Professor Martin Berzins, principal investigator among five University of Utah faculty members who will work on the project. “One of Utah’s main contributions will be the batteries.” Of the five-year Army grant of $14,898,000, the University of Utah will retain $4.2 million for research plus additional administrative costs. The remainder will go to members of the consortium led by the University of Utah, including Boston University, Rensselaer Polytechnic Institute, Pennsylvania State University, Harvard University, Brown University, the University of California, Davis, and the Polytechnic University of Turin, Italy. The new research effort is based on the idea that by using powerful computers to simulate the behavior of materials on multiple scales - from the atomic and molecular nanoscale to the large or “bulk” scale—new, lighter, more energy efficient power supplies and materials can be designed and developed. Improving existing materials also is a goal. ”We want to model everything from the nanoscale to the soldier scale,” Berzins says. “It’s virtual design, in some sense.”

Zinc oxide solar reactor could be a renewable source of hydrogen

Producing hydrogen from non-fossil fuel sources is a problem that continues to elude many scientists but University of Delaware’s Erik Koepf thinks he may have discovered a solution. Koepf, a doctoral candidate in mechanical engineering, has designed a novel reactor that employs highly concentrated sunlight and zinc oxide powder to produce solar hydrogen, a truly clean, sustainable fuel with zero emissions. The reactor, which resembles a large cylinder, is comprised of layers of advanced, ultrahigh temperature insulation and ceramic materials. The conical geometry of the reactor’ design uses gravity to feed zinc oxide powder (the reactant) into the system through 15 hoppers perched on top of the device using special gears and a custom built control assembly Koepf developed at UD. Cooling blocks embedded in the structure keep the motors, a quartz window and the aperture ring, where the sunlight enters, cool. “The idea is to create a small, well-insulated cavity and subject it to highly concentrated sunlight from above,” explains Koepf. Once hot, the hoppers will feed zinc oxide powder (a benign substance resembling baking soda) onto the ceramic layer, causing a reaction that decomposes the powder into pure zinc vapor. In a subsequent step, the zinc will be reacted with water to produce solar hydrogen. “Essentially, we take zinc oxide powder and thermochemically store the energy of the sun in it, then bottle it,” explains Koepf.

Fraunhofer: Feel-good glass for windows

Daylight acts on our body clock and stimulates the brain. Fraunhofer researchers have made use of this knowledge and worked with industry partners to develop a coating for panes of glass that lets through more light. Above all, it promotes the passage through the glass of those wavelengths of light that govern our hormonal balance. Most people prefer to live in homes that are airy and flooded with light. Nobody likes to spend much time in a dark and dingy room. That’s no surprise, since daylight gives us energy and has a major impact on our sense of wellbeing. It is a real mood lifter. Anti-reflective glass that is more transmissive overall to daylight is reserved for certain special applications, such as in glass covers for photovoltaic modules or in glazing for shop windows. The aim with this new kind of glass is to avoid nuisance reflections and to achieve maximum light transmission at the peak emission wavelength of sunlight. This is the wavelength at which the human retina is also most sensitive to light. “However, our biorhythms are not affected by the wavelengths that brighten a room the most, but rather by blue light,” explains graduate engineer Walther Glaubitt, a researcher at the Fraunhofer Institute for Silicate Research ISC in Würzburg. That is why he and his team have developed glass that is designed to be particularly transmissive to light in the blue part of the spectrum. The secret is a special, long-lasting and barely perceptible inorganic coating that is only 0.1 micrometers thick. “Nobody’s ever made glass like this before. It makes you feel as if the window is permanently open,” says Glaubitt. One reason the glass gives this impression is that it exhibits maximum transmission at wavelengths between 450 and 500 nanometers—which is exactly where the effects of blue light are at their strongest.

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Credit: Katie Fehrenbacher, GigaOm.

Bloom Energy is making a big push to establish a foothold along the Eastern Seaboard. Today, Bloom is holding a ground-breaking ceremony a its new “Bloom Box” solid oxide fuel cell manufacturing plant in Newark, Delaware, at a site that was once a Chrysler assembly plant (Bloom’s other manufacturing is in California, and this essentially doubles the company’s capacity). The company also announced several new customers in the East.

Plans for the Delaware manufacturing hub were actually revealed last summer, and the hope then was that the facility would employ 900. No specific job numbers were mentioned in today’s announcement, but the numbers discussed in 2011 are in line with the number of workers at Bloom’s California facility.

Interestingly, the property is owned by the University of Delaware, which is also developing a Science and Technology Campus on grounds, and the hope is that the Bloom facility will provide an anchor for the campus.

One of the deal-sealers for this development is an agreement between Bloom and Delmarva Power & Light, an East Coast utility,  for a whopping 30 MW of Bloom Boxes.

The company also announced several new customers, including Owens Corning, Urban Outfitters, Washington Gas and AT&T (the latter already uses Bloom units in California facilities). Stories surfaced in March that Apple also had reached a deal to install Bloom energy servers in a North Carolina facility.

The company also is rolling out a new line of SOFC units that, according to the company, feature a 20 percent gain in efficiency and double the energy density (based on footprint of the installation).

It also touts that the fuel cells change the energy paradigm for their customers in that the Bloom Boxes will provide the basic power for the companies’ core operations. In other words, instead of the electrical grid providing the basic power and the fuel cells providing backup power, the SOFCs become the primary source and the grid becomes the backup.

Katie Fehrenbacher at GigaOm has the story in an interesting post and the above video interview with Bloom’s Asim Hussein, the company’s director of product marketing.

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