Buckypaper

El Buckypaper le debe sus impresionantes características a los cada vez más populares nanotubos de carbono. Estos pequeñísimos cilindros formados por átomos de carbono, con un diámetro 50.000 veces menor que el de un cabello humano, también son los responsables de la existencia de este material. Al igual que ocurre con otros materiales compuestos, Buckypaper puede laminarse en hojas muy delgadas que luego se “pegan” unas sobre otras para formar paneles extremadamente resistentes. Estos sándwiches se pueden emplear para construir coches y aviones, reemplazando a los metales habituales. Como “bonus especial”, los fabricantes pueden variar las proporciones de sus componentes para hacerlo mejor o peor conductor de la electricidad. Así, es posible tener paneles que son perfectos aislantes de la corriente eléctrica, o conductores tan buenos como el cobre. El compuesto se está desarrollando desde hace unos veinte años en la Universidad de Florida (California). La elaboración del buckypaper se lleva a cabo solo en laboratorios

Luego de dos décadas de estudios y ensayos, el Buckypaper está casi listo para ser aplicado en productos comerciales. Uno de sus primeros usos será la aplicación sobre la estructura de vehículos aéreos y terrestres. Por supuesto, los ingenieros estarán encantados de contar con un material tan fuerte y liviano, y es posible que hasta las carcasas de nuestros teléfonos móviles u ordenadores portátiles se beneficien de sus bondades.

Fuente: http://www.neoteo.com/buckypaper-coches-y-aviones-hechos-de-papel-14044.neo

New NANO Magazine Covers Day-to-Day Applications of Nanotechnology

In the latest issue of NANO magazine, we look at many applications of nanotechnology to our everyday lives, and its promise for the future. This issue takes a look at how nanotechnology is being addressed in architecture, interior design, biomimetics, education, health and education.

Architecture, construction and Interior Design

Nanotechnology in architecture is addressed compelling by Sylvia Leydecker in this issue. She states that innovation-driven materials and products are critical in achieving green construction, which is now at the forefront of much architectural debate. Ms Leydecker believes that nanomaterials have a huge potential in this area, which is yet to be realised, as architects have not yet engaged fully with what is available.

Following on from a plea that architects become more acquainted with nanotechnology, the Decker Yeadon agency in New York has come up with new concepts based on nanotechnology that could shape the future of homes and offices. They so convinced by its benefits that they have just invested in making Buckypaper, a new material which has an electrically conductive coating of multi-walled nanotubes.

Biomimetics

The emphasis on nanoscience and nanotechnology since the early 1990s has provided a significant impetus in mimicking nature, using nanofabrication techniques for commercial applications. Bharat Bhusan takes us on a tour of the natural world and some of its attributes that are leading to new products using biomimetics. George Whitesides

The subject of this month's interview is Harvard Professor George Whitesides. Professor Whitesides is not only successful as an academic, but is also named on over 50 patents. A lifetime of knowledge and experience has led him to a profound understanding of what society needs from science. His view is that, where science thrives on complexity, and unexpected outcomes, society needs simplicity allied to function.

Education and Ethics

One way to improve understanding of nanotechnology is by engaging young people in dialogue about its ethical, legal and social aspects is needed. NANOYOU (Nano for Youth) is a project funded by the European Commission's Seventh Framework Programme that aims to achieve this through an appealing variety of media, games, role playing and other interactions.

The ethical debate on nanotechnology is an exciting one, which poses many complex questions -such as how we perceive nature, as opposed to artefact; the possible redefinition of the norms of health and disease; the likelihood of Transhumanism; the fair distribution of the benefits of nanotechnology; and scientists' responsibility for the consequences of technological innovations. Marc Pavlopoulos explores how we can ask the right questions, and the surprising ways in which society adopts a new technology.

Nanomedicine and the ageing population

This month's article on nanomedicine by Ottilia Saxl, explores the broader issues of how nanotechnology can provide important benefits to an ageing population, in terms of prolonging independence and quality of life for as long as possible, while reducing costs.

The country profile this month is Brazil. Brazil may have been a little later in getting to grips with the potential of nanotechnology, but investment and strong policies linking science and industry are reaping the benefits. Jos d'Albuquerque e Castro who has been involved in nanotechnology in Brazil, both from within University and Government, gives an all-round perspective on the state of the technology and where it is headed.

Countries covered: Brazil, USA, UK, Italy

Products mentioned: LCD Televisions, Lung-on a chip, Self cleaning surfaces

Fuente: http://www.azonano.com/news.asp?newsID=19411

Chemists Report Promising Advance in Fuel-Cell Technology

ScienceDaily (2010) — Creating catalysts that can operate efficiently and last a long time is a big barrier to taking fuel-cell technology from the lab bench to the assembly line. The precious metal platinum has been the choice for many researchers, but platinum has two major downsides: It is expensive, and it breaks down over time in fuel-cell reactions.

The multi-metallic nanoparticle created by Brown University chemists for fuel-cell reactions uses a palladium core and an iron-platinum shell. (Credit: Vismadeb Mazumder & Shouheng Sun, Brown University)

In a new study, chemists at Brown University report a promising advance. They have created a unique core and shell nanoparticle that uses far less platinum yet performs more efficiently and lasts longer than commercially available pure-platinum catalysts at the cathode end of fuel-cell reactions.

The chemistry known as oxygen reduction reaction takes place at the fuel cell's cathode, creating water as its only waste, rather than the global-warming carbon dioxide produced by internal combustion systems. The cathode is also where up to 40 percent of a fuel cell's efficiency is lost, so "this is a crucial step in making fuel cells a more competitive technology with internal combustion engines and batteries," said Shouheng Sun, professor of chemistry at Brown and co-author of the paper in the Journal of the American Chemical Society.

The research team, which includes Brown graduate student and co-author Vismadeb Mazumder and researchers from Oak Ridge National Laboratory in Tennessee, created a five-nanometer palladium (Pd) core and encircled it with a shell consisting of iron and platinum (FePt). The trick, Mazumder said, was in molding a shell that would retain its shape and require the smallest amount of platinum to pull off an efficient reaction. The team created the iron-platinum shell by decomposing iron pentacarbonyl [Fe(CO)₅] and reducing platinum acetylacetonate [Pt(acac)₂], a technique Sun first reported in a 2000 Science paper. The result was a shell that uses only 30 percent platinum, although the researchers say they expect they will be able to make thinner shells and use even less platinum.

"If we don't use iron pentacarbonyl, then the platinum doesn't form on the (palladium) core," Mazumder said.

The researchers demonstrated for the first time that they could consistently produce the unique core-shell structures. In laboratory tests, the palladium/iron-platinum nanoparticles generated 12 times more current than commercially available pure-platinum catalysts at the same catalyst weight. The output also remained consistent over 10,000 cycles, at least ten times longer than commercially available platinum models that begin to deteriorate after 1,000 cycles.

The team created iron-platinum shells that varied in width from one to three nanometers. In lab tests, the group found the one-nanometer shells performed best.

"This is a very good demonstration that catalysts with a core and a shell can be made readily in half-gram quantities in the lab, they're active, and they last," Mazumder said. "The next step is to scale them up for commercial use, and we are confident we'll be able to do that."

Mazumder and Sun are studying why the palladium core increases the catalytic abilities of iron platinum, although they think it has something to do with the transfer of electrons between the core and shell metals. To that end, they are trying to use a chemically more active metal than palladium as the core to confirm the transfer of electrons in the core-shell arrangement and its importance to the catalyst's function.

Miaofang Chi and Karren More at the Oak Ridge Laboratory also contributed to the paper. The U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy funded the research as part of its Fuel Cell Technologies Program.

Encuentran químico altamente oxidante en Marte

Científicos del Instituto de Investigación Nuclear de la Universidad Nacional Autónoma de México (UNAM), la NASA y la Universidad de Arizona detectaron percloratos en la superficie de Marte, un compuesto químico altamente oxidante, que abre nuevas rutas para la búsqueda de vida en el planeta rojo.

"Lo más relevante para la comunidad científica es el descubrimiento del doctor Navarro y su equipo, pues esto podría cambiar nuestra interpretación total de los resultados no orgánicos de Marte y cambiar los últimos 35 años sobre pensamiento sobre Marte", comentó Peter Smith, investigador de la Universidad de Arizona.

En 1975, la NASA lanzó la misión Vikingo, en la que dos robots tomaron muestras de la superficie del planeta. Ahora, la investigación se repitió en el Desierto de Atacama, en Chile, un lugar que emula las condiciones de Marte; los resultados actuales revelaron un error en el proceso de los años 70.

"Al calentar el suelo de Atacama con percloratos, lo que ocurre al subir la temperatura del orden de 200, 250 y 500 grados centígrados es que la descomposición de los percloratos libera oxígeno, produce la combustión, la quema total de compuestos orgánicos. El instrumento ya no detecta compuestos orgánicos no porque no existan en el suelo, sino porque fueron quemados en los hornos", dijo Rafael Navarro González, investigador del Instituto de Ciencias Nucleares de la UNAM.

"Ahora creemos que hay elementos orgánicos en Marte en los niveles en los que encontramos en los desiertos más secos de la tierra y eso es mil veces más de lo establecido en el proyecto Vikingo", agregó Christopher McKay, del Centro de Investigación Ames de la NASA.

De acuerdo con los especialistas, el reto ahora es descifrar si la materia orgánica en la superficie del planeta rojo proviene del bombardeo de meteoritos o si es un indicio de que existe vida propiamente marciana.

"Estos resultados, aunque no demuestran que pudiera haber vida, si abren la posibilidad de que esos compuestos orgánicos pudieran estar relacionados y se requiere mandar más misiones específicas para tratar de estudiar la naturaleza química de que estos compuestos orgánicos pudieran ser de origen biológico", concluyó Navarro González.

Esta investigación servirá para realizar nuevos estudios en la próxima misión al cuarto planeta del Sistema Solar, a finales de 2012.

http://oncetv-ipn.net/noticias/index.php?modulo=despliegue&dt_fecha=2010-09-06&numnota=36

Magnetism's Subatomic Roots: Study of High-Tech Materials Helps Explain Everyday Phenomenon

ScienceDaily (Sep. 4, 2010) — The modern world -- with its ubiquitous electronic devices and electrical power -- can trace its lineage directly to the discovery, less than two centuries ago, of the link between electricity and magnetism. But while engineers have harnessed electromagnetic forces on a global scale, physicists still struggle to describe the dance between electrons that creates magnetic fields.

Two theoretical physicists from Rice University are reporting initial success in that area in a new paper in the Proceedings of the National Academy of Sciences. Their new conceptual model, which was created to learn more about the quantum quirks of high-temperature superconductors and other high-tech materials, has also proven useful in describing the origins of ferromagnetism -- the everyday "magnetism" of compass needles and refrigerator magnets.

"As a theorist, you strive to have exact solutions, and even though our new model is purely theoretical, it does produce results that match what's observed in the real world," said Rice physicist Qimiao Si, the lead author of the paper. "In that sense, it is reassuring to have designed a model system in which ferromagnetism is allowed."

Ferromagnets are what most people think of as magnets. They're the permanently magnetic materials that keep notes stuck to refrigerators the world over. Scientists have long understood the large-scale workings of ferromagnets, which can be described theoretically from a coarse-grained perspective. But at a deeper, fine-grained level -- down at the scale of atoms and electrons -- the origins of ferromagnetism remain fuzzy.

"When we started on this project, we were aware of the surprising lack of theoretical progress that had been made on metallic ferromagnetism," Si said. "Even a seemingly simple question, like why an everyday refrigerator magnet forms out of electrons that interact with each other, has no rigorous answer."

Si and graduate student Seiji Yamamoto's interest in the foundations of ferromagnetism stemmed from the study of materials that were far from ordinary.

Si's specialty is an area of condensed matter physics that grew out of the discovery more than 20 years ago of high-temperature superconductivity. In 2001, Si offered a new theory to explain the behavior of the class of materials that includes high-temperature superconductors. This class of materials -- known as "quantum correlated matter" -- also includes more than 10 known types of ferromagnetic composites.

Si's 2001 theory and his subsequent work have aimed to explain the experimentally observed behavior of quantum-correlated materials based upon the strangely correlated interplay between electrons that goes on inside them. In particular, he focuses on the correlated electron effect that occur as the materials approach a "quantum critical point," a tipping point that's the quantum equivalent of the abrupt solid-to-liquid change that occurs when ice melts.

The quantum critical point that plays a key role in high-temperature superconductivity is the tipping point that marks a shift to antiferromagnetism, a magnetic state that has markedly different subatomic characteristics from ferromagnetism. Because of the key role in high-temperature superconductivity, most studies in the field have focused on antiferromagnetism. In contrast, ferromagnetism -- the more familiar, everyday form of magnetism -- has received much less attention theoretically in quantum-correlated materials.

"So our initial theoretical question was, 'What would happen, in terms of correlated electron effects, when a ferromagnetic material moves through one of these quantum tipping points?" said Yamamoto, who is now a postdoctoral researcher at the National High Magnetic Field Laboratory in Tallahassee, Fla..

To carry out this thought experiment, Si and Yamamoto created a model system that idealizes what exists in nature. Their jumping off point was a well-studied phenomenon known as the Kondo effect -- which also has its roots in quantum magnetic effects. Based on what they knew of this effect, they created a model of a "Kondo lattice," a fine-grained mesh of electrons that behaved like those that had been observed in Kondo studies of real-world materials.

Si and Yamamoto were able to use the model to provide a rigorous answer about the fine-grained origins of metallic ferromagnetism. Furthermore, the ferromagnetic state that was predicted by the model turned out to have quantum properties that closely resemble those observed experimentally in heavy fermion ferromagnets.

"The model is useful because it allows us to predict how real-world materials might behave under a specific set of circumstances," Yamamoto said. "And, in fact, we have been able to use it to explain experimental observations on heavy fermion metals, including both the antiferromagnets as well as the less well understood ferromagnetic materials."

Nuevo Fotocatalizador Con Luz Visible Que Sigue Matando Bacterias Tras Apagarse la Luz

Un equipo de investigadores ha desarrollado una nueva y poderosa arma para la batalla contra las bacterias: Un proceso de desinfección fotocatalítico mejorado que utiliza luz visible para destruir bacterias y virus dañinos, incluso en la oscuridad.

Basado en un nuevo catalizador, el proceso de desinfección puede ser usado para purificar el agua potable, esterilizar instrumentos quirúrgicos y hasta eliminar huellas dactilares no deseadas en componentes electrónicos y ópticos delicados.

El nuevo catalizador también tiene un efecto de memoria catalítico único, que hace que continúe matando agentes patógenos letales hasta 24 horas después de que la luz es apagada.

El grupo de investigación de Jian Ku Shang (Universidad de Illinois) había desarrollado anteriormente un material catalítico que trabajaba con luz visible, en vez de la luz ultravioleta requerida por otros catalizadores. Este progreso posibilitó que el proceso de desinfección pudiera ser activado con luz solar o con lámparas estándar de interiores.

Shang y otros colaboradores de la Universidad de Illinois y la Academia China de Ciencias han mejorado la eficiencia del catalizador. Ahora, cuando la luz es apagada, unas nanopartículas de paladio liberan lentamente electrones capturados, los cuales puede reaccionar entonces con el agua para producir agentes oxidantes adicionales.

En cierto modo, el material "recuerda" que fue irradiado con luz. Este "efecto de memoria" puede durar hasta 24 horas.

Aunque la eficiencia de la desinfección en la oscuridad no es tan alta como cuando hay luz visible, esa actividad adicional a oscuras posibilita el trabajo constante de un mismo sistema de desinfección catalítico, robusto, y accionado por iluminación solar u otra de luz visible.

Además de las aplicaciones germicidas, el nuevo catalizador también podría ser utilizado para eliminar huellas dactilares en superficies ópticas, y en pantallas de ordenadores y de teléfonos móviles.

Otra aplicación del Grafeno :D

James Heath y su grupo de investigadores del California Institute of Technology encontraron, por accidente, una nueva técnica para observar estructuras de moléculas. La técnica consiste en la formación de una capa de grafeno del grosor de un átomo sobre las moléculas depositadas en una mica. Se reportó que dicho recubrimiento dura aproximadamente dos meses.

Como ya se mencionó, ésta técnica se descubrió por accidente al depositar el grafeno en moléculas de agua observando, a través de microscopía de fuerza atómica, que el grafeno tomaba la “forma” estructural atómica del agua. Esta técnica se utilizó para estudiar la formación de capas por parte del agua, descubriéndose que la primera y segunda capa depositada en la mica es del grueso de dos moléculas y su estructura es como la del hielo a temperatura ambiente.

En este momento Heath y colaboradores trabajan para perfeccionar la técnica y poder visualizar estructuras de biomoléculas como anticuerpos.

California Institute of Technology (2010, September 3). Chemists develop simple technique to visualize atomic-scale structures. Consultado en línea: www.sciencedaily.com/releases/2010/09/100902151122.htm