Tag Archives: Finland

Do artists see colour at the nanoscale? It would seem so

I’ve wondered how Japanese artists of the 16th to 18th centuries were able to beat gold down to the nanoscale for application to screens. How could they see what they were doing? I may have an answer at last. According to some new research, it seems that the human eye can detect colour at the nanoscale.

Before getting to the research, here’s the Namban screen story.

Japanese Namban Screen. ca. 1550. In Portugal-Japão: 450 anos de memórias. Embaixada de Portugal no Japão, 1993. [downloaded from http://www.indiana.edu/~liblilly/digital/exhibitions/exhibits/show/portuguese-speaking-diaspora/china-and-japan]

Japanese Namban Screen. ca. 1550. In Portugal-Japão: 450 anos de memórias. Embaixada de Portugal no Japão, 1993. [downloaded from http://www.indiana.edu/~liblilly/digital/exhibitions/exhibits/show/portuguese-speaking-diaspora/china-and-japan]

This image is from an Indiana University at Bloomington website featuring a page titled, Portuguese-Speaking Diaspora,

A detail from one of four large folding screens on display in the Museu de Arte Antiga in Lisbon. Namban was the word used to refer to Portuguese traders who, in this scene, are dressed in colorful pantaloons and accompanied by African slaves. Jesuits appear in black robes, while the Japanese observe the newcomers from inside their home. The screen materials included gold-covered copper and paper, tempera paint, silk, and lacquer.

Copyright © 2015 The Trustees of Indiana University

Getting back to the Japanese artists, here’s how their work was described in a July 2, 2014 Springer press release on EurekAlert,

Ancient Japanese gold leaf artists were truly masters of their craft. An analysis of six ancient Namban paper screens show that these artifacts are gilded with gold leaf that was hand-beaten to the nanometer scale. [emphasis mine] Study leader Sofia Pessanha of the Atomic Physics Center of the University of Lisbon in Portugal believes that the X-ray fluorescence technique her team used in the analysis could also be used to date other artworks without causing any damage to them. The results are published in Springer’s journal Applied Physics A: Materials Science & Processing.

Gold leaf refers to a very thin sheet made from a combination of gold and other metals. It has almost no weight and can only be handled by specially designed tools. Even though the ancient Egyptians were probably the first to gild artwork with it, the Japanese have long been credited as being able to produce the thinnest gold leaf in the world. In Japanese traditional painting, decorating with gold leaf is named Kin-haku, and the finest examples of this craft are the Namban folding screens, or byobu. These were made during the late Momoyama (around 1573 to 1603) and early Edo (around 1603 to 1868) periods.

Pessanha’s team examined six screens that are currently either part of a museum collection or in a private collection in Portugal. Four screens belong to the Momoyama period, and two others were decorated during the early Edo period. The researchers used various X-ray fluorescence spectroscopy techniques to test the thickness and characteristics of the gold layers. The method is completely non-invasive, no samples needed to be taken, and therefore the artwork was not damaged in any way. Also, the apparatus needed to perform these tests is portable and can be done outside of a laboratory.

The gilding was evaluated by taking the attenuation or weakening of the different characteristic lines of gold leaf layers into account. The methodology was tested to be suitable for high grade gold alloys with a maximum of 5 percent influence of silver, which is considered negligible.

The two screens from the early Edo period were initially thought to be of the same age. However, Pessanha’s team found that gold leaf on a screen kept at Museu Oriente in Lisbon was thinner, hence was made more recently. This is in line with the continued development of the gold beating techniques carried out in an effort to obtain ever thinner gold leaf.

So, how did these artists beat gold leaf down to the nanoscale and then use the sheets in their art work? This July 10, 2015 news item on Azonano may help to answer that question,

The human eye is an amazing instrument and can accurately distinguish between the tiniest, most subtle differences in color. Where human vision excels in one area, it seems to fall short in others, such as perceiving minuscule details because of the natural limitations of human optics.

In a paper published today in The Optical Society’s new, high-impact journal Optica, a research team from the University of Stuttgart, Germany and the University of Eastern Finland, Joensuu, Finland, has harnessed the human eye’s color-sensing strengths to give the eye the ability to distinguish between objects that differ in thickness by no more than a few nanometers — about the thickness of a cell membrane or an individual virus.

A July 9, 2015 Optical Society news release (also on EurkeAlert), which originated the news item, provides more details,

This ability to go beyond the diffraction limit of the human eye was demonstrated by teaching a small group of volunteers to identify the remarkably subtle color differences in light that has passed through thin films of titanium dioxide under highly controlled and precise lighting conditions. The result was a remarkably consistent series of tests that revealed a hitherto untapped potential, one that rivals sophisticated optics tools that can measure such minute thicknesses, such as ellipsometry.

“We were able to demonstrate that the unaided human eye is able to determine the thickness of a thin film — materials only a few nanometers thick — by simply observing the color it presents under specific lighting conditions,” said Sandy Peterhänsel, University of Stuttgart, Germany and principal author on the paper. The actual testing was conducted at the University of Eastern Finland.

The Color and Thickness of Thin Films

Thin films are essential for a variety of commercial and manufacturing applications, including anti-reflective coatings on solar panels. These films can be as small as a few to tens of nanometers thick. The thin films used in this experiment were created by applying layer after layer of single atoms on a surface. Though highly accurate, this is a time-consuming procedure and other techniques like vapor deposition are used in industry.

The optical properties of thin films mean that when light interacts with their surfaces it produces a wide range of colors. This is the same phenomenon that produces scintillating colors in soap bubble and oil films on water.

The specific colors produced by this process depend strongly on the composition of the material, its thickness, and the properties of the incoming light. This high sensitivity to both the material and thickness has sometimes been used by skilled engineers to quickly estimate the thickness of films down to a level of approximately 10-20 nanometers.

This observation inspired the research team to test the limits of human vision to see how small of a variation could be detected under ideal conditions.

“Although the spatial resolving power of the human eye is orders of magnitude too weak to directly characterize film thicknesses, the interference colors are well known to be very sensitive to variations in the film,” said Peterhänsel.

Experimental Setup

The setup for this experiment was remarkably simple. A series of thin films of titanium dioxide were manufactured one layer at a time by atomic deposition. While time consuming, this method enabled the researchers to carefully control the thickness of the samples to test the limitations of how small a variation the research subjects could identify.

The samples were then placed on a LCD monitor that was set to display a pure white color, with the exception of a colored reference area that could be calibrated to match the apparent surface colors of the thin films with various thicknesses.

The color of the reference field was then changed by the test subject until it perfectly matched the reference sample: correctly identifying the color meant they also correctly determined its thickness. This could be done in as little as two minutes, and for some samples and test subjects their estimated thickness differed only by one-to-three nanometers from the actual value measured by conventional means. This level of precision is far beyond normal human vision.

Compared to traditional automated methods of determining the thickness of a thin film, which can take five to ten minutes per sample using some techniques, the human eye performance compared very favorably.

Since human eyes tire very easily, this process is unlikely to replace automated methods. It can, however, serve as a quick check by an experienced technician. “The intention of our study never was solely to compare the human color vision to much more sophisticated methods,” noted Peterhänsel. “Finding out how precise this approach can be was the main motivation for our work.”

The researchers speculate that it may be possible to detect even finer variations if other control factors are put in place. “People often underestimate human senses and their value in engineering and science. This experiment demonstrates that our natural born vision can achieve exceptional tasks that we normally would only assign to expensive and sophisticated machinery,” concludes Peterhänsel.

Here’s a link to and a citation for the paper,

Human color vision provides nanoscale accuracy in thin-film thickness characterization by Sandy Peterhänsel, Hannu Laamanen, Joonas Lehtolahti, Markku Kuittinen, Wolfgang Osten, and Jani Tervo. Optica Vol. 2, Issue 7, pp. 627-630 (2015) •doi: 10.1364/OPTICA.2.000627

This article appears to be open access.

It would seem that the artists creating the Namban screens exploited the ability to see at the nanoscale, which leads me to  wonder how many people who work with color/colour all the time such as visual artists, interior designers, graphic designers, printers, and more can perceive at the nanoscale. These German and Finnish researchers may want to work with some of these professionals in their next study.

2015 Science & You, a science communication conference in France

Science communicators can choose to celebrate June 2015 in Nancy, France and acquaint themselves with the latest and greatest in communication at the Science & You conference being held from June 1 – 6, 2015. Here’s the conference teaser being offered by the organizers,

The 2015 conference home page (ETA May 5, 2015 1045 hours PDT: the home page features change) offers this sampling of the workshops on offer,

No less than 180 communicators will be lined up to hold workshop sessions, from the 2nd to the 5th June in Nancy’s Centre Prouvé. In the meantime, here is an exclusive peek at some of the main themes which will be covered:

– Science communication and journalism. Abdellatif Bensfia will focus on the state of science communication in a country where major social changes are playing out, Morocco, while Olivier Monod will be speaking about “Chercheurs d’actu” (News Researchers), a system linking science with the news. Finally, Matthieu Ravaud and Fabrice Impériali from the CNRS (Centre National de Recherche Scientifique) will be presenting “CNRS Le journal”, the new on-line media for the general public.

– Using animals in biomedical research. This round-table, chaired by Victor Demaria-Pesce, from the Groupement Interprofessionnel de Réflexion et de Communication sur la Recherche (Gircor) will provide an opportunity to spotlight one of society’s great debates: the use of animals in research. Different actors working in biomedical research will present their point of view on the subject, and the results of an analysis of public perception of animal experimentation will be presented. What are the norms in this field? What are the living conditions of the animals in laboratories? How is this research to be made legitimate? This session will centre on all these questions.

– Science communication and the arts. This session will cover questions such as the relational interfaces between art and science, with in particular the presentation of “Pulse Project” with Michelle Lewis-King, and the Semaine du Cerveau (Brain Week) in Grenoble (Isabelle Le Brun).
Music will also be there with the talk by Milla Karvonen from the University of Oulu, who will be speaking about the interaction between science and music, while Philippe Berthelot will talk about the art of telling the story of science as a communication tool.

– Science on television. This workshop will also be in the form of a round table, with representatives from TVV (Vigyan Prasar, Inde), and Irene Lapuente (La Mandarina de Newton), Mico Tatalovic and Elizabeth Vidal (University of Cordoba), discussing how the world of science is represented on a mass media like television. Many questions will be debated, as for example the changing image of science on television, its historical context, or again, the impact these programmes have on audiences’ perceptions of science.

To learn more, you will find the detailed list of all the workshops and plenaries in the provisional programme on-line.

Science & You seems to be an ‘umbrella brand’ for the “Journées Hubert Curien” conference with plenaries and workshops and the “Science and Culture” forum, which may explain the variety of dates (June 1 – 6, June 2 – 5, and June 2 – 6) on the Science & You home page.

Here’s information about the Science & You organizers and more conference dates (from the Patrons page),

At the invitation of the President of the Université de Lorraine, the professors Etienne Klein, Cédric Villani and Brigitte Kieffer accepted to endorse Science & You. It is an honour to be able to associate them with this major event in science communication, in which they are particularly involved.

Cédric Villani, Fields Medal 2010

Cédric Villani is a French mathematician, the Director of the Institut Henri Poincaré and a professor at the Université Claude Bernard Lyon 1.
His main research interests are in kinetic theory (Boltzmann and Vlasov equations and their variants), and optimal transport and its applications (Monge equation).
He has received several national and international awards for his research, in particular the Fields Medal, which he received from the hands of the President of India at the 2010 International Congress of Mathematicians in Hyderabad (India). Since then he has played the role of spokesperson for the French mathematical community in media and political circles.
Cédric Villani regularly invests in science communication aiming at various audiences: conferences in schools, public conferences in France and abroad, regular participation in broadcasts and current affairs programmes and in science festivals.

Etienne Klein, physicist and philosopher

Etienne Klein is a French physicist, Director of Research at the CEA (Commissariat à l’énergie atomique et aux énergies alternatives – Alternative Energies and Atomic Energy Commission) and has a Ph.D. in philosophy of science. He teaches at the Ecole Centrale in Paris and is head of the Laboratoire de Recherche sur les Sciences de la Matière (LARSIM) at the CEA.

He has taken part in several major projects, such as developing a method of isotope separation involving the use of lasers, and the study of a particle accelerator with superconducting cavities. He was involved in the design of the Large Hadron Collider (LHC) at CERN.
He taught quantum physics and particle physics at Ecole Centrale in Paris for several years and currently teaches philosophy of science. He is a specialist on time in physics and is the author of a number of essays.
He is also a member of the OPECST (Conseil de l’Office parlementaire d’évaluation des choix scientifiques et technologiques – Parliamentary Office for the Evaluation of Scientific and Technological Choices), of the French Academy of Technologies, and of the Conseil d’Orientation (Advisory Board) of the Institut Diderot.
Until June 2014, he presented a weekly radio chronicle, Le Monde selon Etienne Klein, on the French national radio France Culture.

Photo by Philippe Matsas © Flammarion

Brigitte Kieffer, Campaigner for women in science

B. L. Kieffer is Professor at McGill University and at the Université de Strasbourg France. She is also Visiting Professor at UCLA (Los Angeles, USA). She develops her research activity at IGBMC, one of the leading European centres of biomedical research. She is recipient of the Jules Martin (French Academy of Science, 2001) and the Lounsbery (French and US Academies of Science, 2004) Awards, and has become an EMBO Member in 2009.
In 2012 she received the Lamonica Award of Neurology (French Academy of Science) and was nominated Chevalier de la Légion d’honneur. In December 2013 she was elected as a member of the French Academy of Sciences.
In March 2014, she received the International L’OREAL-UNESCO Award for Women in Science (European Laureate). She started as the Scientific Director of the Douglas Hospital Research Centre, affiliated to McGill University in January 2014, and remains Professor at the University of Strasbourg, France.

Photo by Julian Dufort

Here’s more about the conference at the heart of Science & You (from The Journées Hubert Curien International Conference webpage),

Following on the 2012 conference, this project will bring together all those interested in science communication: researchers, PhD students, science communicators, journalists, professionals from associations and museums, business leaders, politicians… A high-level scientific committee has been set up for this international conference, chaired by Professor Joëlle Le Marec, University of Paris 7, and counting among its members leading figures in science communication such as Bernard Schiele (Canada) or Hester du Plessis (South Africa).

The JHC Conference will take place from June 2nd to 6th at the Centre Prouvé, Nancy. These four days will be dedicated to a various programme of plenary conferences and workshops on the theme of science communication today and tomorrow.

You can find the Registration webpage here where you can get more information about the process and access the registration form.

Partners wanted to commercialize new production technique for metallic nanoparticles

An April 20, 2015 news item on Azonano announces a new technique for producing metallic nanoparticles (Note: A link has been removed),

Researchers at VTT Technical Research Centre of Finland Ltd have devised a new, inexpensive metallic nanoparticle manufacturing technique.

The aerosol technology reactor employed for nanoparticle synthesis is capable of producing carbon-coated particles, particles of various alloys and a number of pure metal particles. It can even produce several grams and kilograms of nanoparticles every day.

Nanoparticles are suitable for applications including energy technology, tailoring the electrical and magnetic properties of polymers, drug dosing and medical diagnostics, and conductive and magnetic inks. VTT is looking forward to commercialize the technique.

An April 20, 2015 VTT press release (also on EurekAlert), which originated the news item,  describes the project’s achievements in more detail and makes a plea (of sorts) for partners to commercialize this work,

“Demand has outstripped supply in the nanoparticle markets. This has been an obstacle to the development of product applications; nano-metal composites are scarce and often available in small quantities only. We wanted to demonstrate that it was possible to produce nanomaterials in considerable quantities cost-effectively,” comments Ari Auvinen of VTT, head of the research team.

When developing the reactor, the aim was to achieve a production figure of 200-3,000 grammes per day. This has already been clearly exceeded. Due to the extremely small material wastage incurred when using this equipment, remote-control production can be maintained for several days. In most cases, industrial production of metallic nanoparticles involves chemical reduction in liquid solutions, which requires the design of product-specific solutions. Plasma synthesis, which consumes large amounts of energy and involves significant material wastage, is another generally used method.

In the design of the reactor developed by VTT, the scalability and cost-effectiveness of the synthesis process were key criteria. For this reason, synthesis is performed under air pressure at a comparatively low temperature. This means that the equipment can be built from materials commonly used in industry and energy consumption is low. The process generates an extremely high particle concentration, enabling a high production speed but with low gas consumption. In addition, even impure metallic salts can be used as a raw material, which keeps the price low.

VTT has demonstrated the practical functionality of its reactor by testing the production of various nanometals, metallic compounds and carbon-coated materials. Materials such as carbon-coated magnets, which can be used as catalysts in biorefineries – say, in the production of biofuels – have been produced in the reactor. Following synthesis, magnets used as catalysts can be efficiently gathered in and recycled back into the process.

Nanoparticles have also been tested in the manufacture of magnetic inks and inks that conduct electricity in printed electronics. For example, VTT succeeded in using a permalloy ink to print a magnetically anisotropic material, which can be used in the manufacture of magnetic field sensors.

VTT’s third application trial involved the prevention of microwave reflection. The tests showed that reflection can be reduced by even 10,000 times in polymers, by adding particles which increase radar wave attenuation.

VTT’s researchers believe that the reactor has many applications in addition to those already mentioned. The silicon nanoparticles it produces may even enable lithium battery capacity to be boosted by a factor of 10. Other possible applications, all of which require further investigation, include high permeability polymers, nanomagnets for medical diagnostics applications, materials for the 3D printing of metal articles, and silicon-based materials for thermoelectric and solar power components.

VTT is currently seeking a party interested in commercialising the technique.

For interested parties, here is the contact information listed in the press release,

For more information, please contact:

Raimo Korhonen, Head of Research Area
tel. +358 40 7030052, raimo.korhonen@vtt.fi

Good luck!

Ink toner on paper: research into topographies

An April 14, 2015 news item on Nanowerk about pen (in this case, ink toner) and paper,

A team of Finnish scientists has found a new way to examine the ancient art of putting ink to paper in unprecedented 3-D detail. The technique could improve scientists’ understanding of how ink sticks to paper and ultimately lead to higher quality, less expensive and more environmentally-friendly printed products.

Using modern X-ray and laser-based technologies, the researchers created a nano-scale map of the varying thickness of toner ink on paper. They discovered that wood fibers protruding from the paper received relatively thin coatings of ink. In general, they also found the toner thickness was dictated mainly by the local changes in roughness, rather than the chemical variations caused by the paper’s uneven glossy finish.

“We believe that this gives new insight, especially on how the topography of paper impacts the ink setting or consolidation,” said Markko Myllys, an applied physicist at the University of Jyvaskyla in Finland. “This in turn helps us understand how glossy and non-glossy printed surfaces should be made.”

An April 14, 2016 American Institute of Physics (AIP) news release (also on EurekAlert) by Catherine Myers, which originated the news item, describes the research in more detail,

To achieve their detailed picture of ink thickness, the researchers first examined the underlying paper with X-ray microtomography, a smaller cousin of the CT scanning technology used in hospitals to produce images of the inside of the body.

To analyze the cyan ink layers, the researchers used two additional technologies: optical profilometry, which bounced a light beam off the surface of the ink to obtain a surface profile, and laser ablation, which zapped away controlled amounts of ink with a laser to determine the ink depth.

Although none of the imaging techniques are themselves new, the researchers were the first to combine all three to achieve a complete, high-resolution 3-D image of the intricate ink and paper microstructures.

The final images resemble a rugged mountain landscape, with the higher peaks generally showing thinner coatings of ink, and the valleys showing thicker pools.

The researchers found the typical ink layer was approximately 2.5 micrometers deep, about 1/40 the thickness of an average sheet of paper, but with relatively large spatial variations between the thickest and thinnest areas.

Knowing how topographical variations affect ink thickness will help the printing industry create more environmentally-friendly and less energy-demanding ink and optimize the size distribution of ink particles, Myllys said. It could also help the papermaking industry design more sustainable paper and packaging, for example from recycled components, while still maintaining the quality needed to make ink stick well. Additionally, the papermaking industry could use the findings to help decide how best to incorporate smart and novel features into paper, Myllys said.

The team believes the imaging methods they used can also be adapted to effectively analyze the thickness variations in other types of thin films, including those found in microelectronics, wear-resistant coatings and solar panels.

“This result can certainly be generalized, and that makes it actually quite interesting,” Myllys said. “Thickness variations of thin films are crucial in many applications, but the 3-D analysis has been very difficult or impossible until now.”

Here’s a link to and a citation for the paper,

X-ray microtomography and laser ablation in the analysis of ink distribution in coated paper by  M. Myllys, H. Häkkänen, Korppi-Tommola, K. Backfolk, P. Sirviö, and J. Timonen1. J. Appl. Phys. 117, 144902 (2015); http://dx.doi.org/10.1063/1.4916588

This paper appears to be open access.

Gold atoms: sometimes they’re a metal and sometimes they’re a molecule

Fascinating work out of Finland shows that a minor change in the number of gold atoms in your gold nanoparticle can mean the difference between a metal and a molecule (coincidentally, this phenomenon is alluded to in my April 14, 2015 post (Nature’s patterns reflected in gold nanoparticles); more about that at the end of this piece. Getting back to Finland and when gold is metal and when it’s a molecule, here’s more from an April 10, 2015 news item on ScienceDaily,

Researchers at the Nanoscience Center at the University of Jyväskylä, Finland, have shown that dramatic changes in the electronic properties of nanometre-sized chunks of gold occur in well-defined size range. Small gold nanoclusters could be used, for instance, in short-term storage of energy or electric charge in the field of molecular electronics. Funded by the Academy of Finland, the researchers have been able to obtain new information which is important, among other things, in developing bioimaging and sensing based on metal-like clusters.

An April 10, 2015 news release (also on EurekAlert) on the Academy of Finland (Suomen Akatemia) website, which originated the news item, describes the work in more detail,

Two recent papers by the researchers at Jyväskylä (1, 2) demonstrate that the electronic properties of two different but still quite similar gold nanoclusters can be drastically different. The clusters were synthesised by chemical methods incorporating a stabilising ligand layer on their surface. The researchers found that the smaller cluster, with up to 102 gold atoms, behaves like a giant molecule while the larger one, with at least 144 gold atoms, already behaves, in principle, like a macroscopic chunk of metal, but in nanosize.

The fundamentally different behaviour of these two differently sized gold nanoclusters was demonstrated by shining a laser light onto solution samples containing the clusters and by monitoring how energy dissipates from the clusters into the surrounding solvent.

“Molecules behave drastically different from metals,” said Professor Mika Pettersson, the principal investigator of the team conducting the experiments. “The additional energy from light, absorbed by the metal-like clusters, transfers to the environment extremely rapidly, in about one hundred billionth of a second, while a molecule-like cluster is excited to a higher energy state and dissipates the energy into the environment with a rate that is at least 100 times slower. This is exactly what we saw: the 102-gold atom cluster is a giant molecule showing even a transient magnetic state while the 144-gold atom cluster is already a metal. We’ve thus managed to bracket an important size region where this fundamentally interesting change in the behaviour takes place.”

“These experimental results go together very well with what our team has seen from computational simulations on these systems,” said Professor Hannu Häkkinen, a co-author of the studies and the scientific director of the nanoscience centre. “My team predicted this kind of behaviour back in 2008-2009 when we saw big differences in the electronic structure of exactly these nanoclusters. It’s wonderful that robust spectroscopic experiments have now proved these phenomena. In fact, the metal-like 144-atom cluster is even more interesting, since we just published a theoretical paper where we saw a big enhancement of the metallic properties of just a few copper atoms mixed with gold.” (3)

Here are links to and citation for the papers,

Ultrafast Electronic Relaxation and Vibrational Cooling Dynamics of Au144(SC2H4Ph)60 Nanocluster Probed by Transient Mid-IR Spectroscopy by Satu Mustalahti, Pasi Myllyperkiö, Tanja Lahtinen, Kirsi Salorinne, Sami Malola, Jaakko Koivisto, Hannu Häkkinen, and Mika Pettersson. J. Phys. Chem. C, 2014, 118 (31), pp 18233–18239 DOI: 10.1021/jp505464z Publication Date (Web): July 3, 2014

Copyright © 2014 American Chemical Society

Copper Induces a Core Plasmon in Intermetallic Au(144,145)–xCux(SR)60 Nanoclusters by Sami Malola, Michael J. Hartmann, and Hannu Häkkinen. J. Phys. Chem. Lett., 2015, 6 (3), pp 515–520 DOI: 10.1021/jz502637b Publication Date (Web): January 22, 2015

Copyright © 2015 American Chemical Society

Molecule-like Photodynamics of Au102(pMBA)44 Nanocluster by Satu Mustalahti, Pasi Myllyperkiö, Sami Malola, Tanja Lahtinen, Kirsi Salorinne, Jaakko Koivisto, Hannu Häkkinen, and Mika Pettersson. ACS Nano, 2015, 9 (3), pp 2328–2335 DOI: 10.1021/nn506711a Publication Date (Web): February 22, 2015

Copyright © 2015 American Chemical Society

These papers are behind paywalls.

As for my April 14, 2015 post (Nature’s patterns reflected in gold nanoparticles), researchers at Carnegie Mellon University were researching patterns in different sized gold nanoparticles when this was noted in passing,

… Normally, gold is one of the best conductors of electrical current, but the size of Au133 is so small that the particle hasn’t yet become metallic. …

Nano for car lubricants and for sensors on dashboards

I have two car-oriented news items today. The first concerns the introduction of carbon nanospheres into lubricants as a means of reducing friction. From a March 5, 2015 news item on Nanowerk,

Tiny, perfectly smooth carbon spheres added to motor oil have been shown to reduce friction and wear typically seen in engines by as much as 25 percent, suggesting a similar enhancement in fuel economy.

The researchers also have shown how to potentially mass-produce the spheres, making them hundreds of times faster than previously possible using ultrasound to speed chemical reactions in manufacturing.

“People have been making these spheres for about the last 10 years, but what we discovered was that instead of taking the 24 hours of synthesis normally needed, we can make them in 5 minutes,” said Vilas Pol, an associate professor of chemical engineering at Purdue University.

The spheres are 100-500 nanometers in diameter, a range that generally matches the “surface roughness” of moving engine components.

“So the spheres are able to help fill in these areas and reduce friction,” said mechanical engineering doctoral student Abdullah A. Alazemi.

A March 4, 2015 Purdue University news release by Emil Venere, which originated the news item, elaborates on the impact this finding could have (Note: A link has been removed),

Tests show friction is reduced by 10 percent to 25 percent when using motor oil containing 3 percent of the spheres by weight.

“Reducing friction by 10 to 25 percent would be a significant improvement,” Sadeghi said. “Many industries are trying to reduce friction through modification of lubricants. The primary benefit to reducing friction is improved fuel economy.”

Friction is greatest when an engine is starting and shutting off, so improved lubrication is especially needed at those times.

“Introducing microspheres helps separate the surfaces because the spheres are free to move,” Alazemi said. “It also is possible that these spheres are rolling and acting as little ball bearings, but further research is needed to confirm this.” [emphasis mine]

Findings indicate adding the spheres did not change the viscosity of the oil.

“It’s very important not to increase the viscosity because you want to maintain the fluidity of the oil so that it can penetrate within engine parts,” Alazemi said.

The spheres are created using ultrasound to produce bubbles in a fluid containing a chemical compound called resorcinol and formaldehyde. The bubbles expand and collapse, generating heat that drives chemical reactions to produce polymer particles. These polymeric particles are then heated in a furnace to about 900 degrees Celsius, yielding the perfectly smooth spheres.

“A major innovation is that professor Pol has shown how to make lots of these spheres, which is important for potential industrial applications,” Sadeghi said.

Etacheri said, “Electron microscopy images and Raman spectra taken before and after their use show the spheres are undamaged, suggesting they can withstand the punishing environment inside engines and other machinery.”

Funding was provided by Purdue’s School of Chemical Engineering. Electron microscopy studies were performed at the Birck Nanotechnology Center in Purdue’s Discovery Park.

Future research will include work to determine whether the spheres are rolling like tiny ball bearings or merely sliding. A rolling mechanism best reduces friction and would portend well for potential applications. Future research also will determine whether the resorcinol-formaldehyde particles might themselves be used as a lubricant additive without heating them to produce pure carbon spheres.

I’m not sure why the researcher is referring to microspheres as the measurements are at the nanoscale, which should mean these are ‘nanospheres’ or, as the researchers have it in the title for their paper, ‘submicrometer spheres’.

Here’s a link to and a citation for the paper,

Ultrasmooth Submicrometer Carbon Spheres as Lubricant Additives for Friction and Wear Reduction by Abdullah A. Alazemi, Vinodkumar Etacheri, Arthur D. Dysart, Lars-Erik Stacke, Vilas G. Pol, and Farshid Sadeghi. ACS Appl. Mater. Interfaces, Article ASAP DOI: 10.1021/acsami.5b00099 Publication Date (Web): February 17, 2015
Copyright © 2015 American Chemical Society

This paper is behind a paywall but there is an instructive image freely available,

This image taken with an electron microscope shows that tiny carbon spheres added to motor oil reduce friction and wear typically seen in engines by as much as 25 percent, suggesting a similar enhancement in fuel economy. Purdue researchers also have shown how to potentially mass-produce the spheres. (Purdue University image)

This image taken with an electron microscope shows that tiny carbon spheres added to motor oil reduce friction and wear typically seen in engines by as much as 25 percent, suggesting a similar enhancement in fuel economy. Purdue researchers also have shown how to potentially mass-produce the spheres. (Purdue University image)

My second car item concerns thin films and touch. From a March 5, 2015 news item on Azonano (Note: A link has been removed),,

Canatu, a leading manufacturer of transparent conductive films, has in partnership with Schuster Group [based in Germany] and Display Solution AG [based in Germany], showcased a pioneering 3D encapsulated touch sensor for the automotive industry.

The partnership is delivering the first ever, button free, 3D shaped true multitouch panel for automotives, being the first to bring much anticipated touch applications to dashboards and paneling. The demonstrator provides an example of multi-functional display with 5 finger touch realized in IML [in mould labeling] technology.

A March 5, 2015 Canatu press release, which originated the news item, provides more details about the technology and some insight into future plans,

The demonstrator provides an example of multi-functional display with 5 finger touch realized in IML technology. The integration of touch applications to dashboards and other paneling in cars has long been a desired by automotive designers but a suitable technology was not available. Finally the technology is now here. Canatu’s CNB™ (Carbon NanoBud®) In-Mold Film, with its unique stretch properties provides a clear path to the eventual replacement of mechanical controls with 3D touch sensors. The touch application was made using an existing mass manufacturing tool and industry standard processes.

Specifically designed for automobile center consoles and dashboards, household machines, wearable devices, industrial user interfaces, commercial applications and consumer devices, CNB™ In-Mold Films can be easily formed into shape. The film is first patterned to the required touch functionality, then formed, then back-molded by injection molding, resulting in a unique 3D shape with multitouch functionality.

With a bending radius of 1mm, CNB™ In-Mold Films can bring touch to almost any surface imaginable. The unique properties of CNB™ In-Mold Films are unmatched as no other film on the market can be stretched 120% and molded without losing their conductivity.

You can find out more about Canatu, based in Finland, here.

Europe’s search for raw materials and hopes for nanotechnology-enabled solutions

A Feb. 27, 2015 news item on Nanowerk highlights the concerns over the availability of raw materials and European efforts to address those concerns,

Critical raw materials’ are crucial to many European industries but they are vulnerable to scarcity and supply disruption. As such, it is vital that Europe develops strategies for meeting the demand for raw materials. One such strategy is finding methods or substances that can replace the raw materials that we currently use. With this in mind, four EU projects working on substitution in catalysis, electronics and photonics presented their work at the Third Innovation Network Workshop on substitution of Critical Raw Materials hosted by the CRM_INNONET project in Brussels earlier this month [February 2015].

A Feb. 26, 2015 CORDIS press release, which originated the news item, goes on to describe four European Union projects working on nanotechnology-enabled solutions,


NOVACAM, a coordinated Japan-EU project, aims to develop catalysts using non-critical elements designed to unlock the potential of biomass into a viable energy and chemical feedstock source.

The project is using a ‘catalyst by design’ approach for the development of next generation catalysts (nanoscale inorganic catalysts), as NOVACAM project coordinator Prof. Emiel Hensen from Eindhoven University of Technology in the Netherlands explained. Launched in September 2013, the project is developing catalysts which incorporate non-critical metals to catalyse the conversion of lignocellulose into industrial chemical feedstocks and bio-fuels. The first part of the project has been to develop the principle chemistry while the second part is to demonstrate proof of process. Prof. Hensen predicts that perhaps only two of three concepts will survive to this phase.

The project has already made significant progress in glucose and ethanol conversion, according to Prof. Hensen, and has produced some important scientific publications. The consortium is working with and industrial advisory board comprising Shell in the EU and Nippon Shokubai in Japan.


The FREECATS project, presented by project coordinator Prof. Magnus Rønning from the Norwegian University of Science and Technology, has been working over the past three years to develop new metal-free catalysts. These would be either in the form of bulk nanomaterials or in hierarchically organised structures – both of which would be capable of replacing traditional noble metal-based catalysts in catalytic transformations of strategic importance.

Prof. Magnus Rønning explained that the application of the new materials could eliminate the need for the use for platinum group metals (PGM) and rare earth metals – in both cases Europe is very reliant on other countries for these materials. Over the course of its research, FREECATS targeted three areas in particular – fuel cells, the production of light olefins and water and wastewater purification.

By working to replace the platinum in fuel cells, the project is supporting the EU’s aim of replacing the internal combustion engine by 2050. However, as Prof. Rønning noted, while platinum has been optimized for use over several decades, the materials FREECATS are using are new and thus come with their new challenges which the project is addressing.


Prof. Atsufumi Hirohata of the University of York in the United Kingdom, project coordinator of HARFIR, described how the project aims to discover an antiferromagnetic alloy that does not contain the rare metal Iridium. Iridium is becoming more and more widely used in numerous spin electronic storage devices, including read heads in hard disk drives. The world supply depends on Platinum ore that comes mainly from South Africa. The situation is much worse than for other rare earth elements as the price has been shooting up over recent years, according to Prof. Hirohata.

The HARFIR team, divided between Europe and Japan, aims to replace Iridium alloys with Heusler alloys. The EU team, led by Prof. Hirohata, has been working on the preparation of polycrystalline and epitaxial thin films of Heusler Alloys, with the material design led by theoretical calculations. The Japanese team, led by Prof. Koki Takanashi at Tohoku University, is meanwhile working on the preparation of epitaxial thin films, measurements of fundamental properties and structural/magnetic characterisation by neutron and synchrotron x-ray beams.

One of the biggest challenges has been that Heusler alloys have a relatively complicated atomic structure. In terms of HARFIR’s work, if any atomic disordering at the edge of nanopillar devices, the magnetic properties that are needed are lost. The team is exploring solutions to this challenge.


Prof. of Esko Kauppinen Aalto University in Finland closed off the first session of the morning with his presentation of the IRENA project. Launched in September 2013, the project will run until mid 2017 working towards the aim of developing high performance materials, specifically metallic and semiconducting single-walled carbon nanotube (SWCNT) thin films to completely eliminate the use of the critical metals in electron devices. The ultimate aim is to replace Indium in transparent conducting films, and Indium and Gallium as a semiconductor in thin film field effect transistors (TFTs).

The IRENA team is developing an alternative that is flexible, transparent and stretchable so that it can meet the demands of the electronics of the future – including the possibility to print electronics.

IRENA involves three partners from Europe and three from Japan. The team has expertise in nanotube synthesis, thin film manufacturing and flexible device manufacturing, modelling of nanotube growth and thin film charge transport processes, and the project has benefitted from exchanges of team members between institutions. One of the key achievements so far is that the project has succeeded in using a nanotube thin film for the first time as the both the electrode and hole blocking layer in an organic solar cell.

You’ll note that Japan is a partner in all of these projects. In all probability, these initiatives have something to do with rare earths which are used in much of today’s electronics technology and Japan is sorely lacking in those materials. China, by comparison, has dominated the rare earths export industry and here’s an excerpt from my Nov. 1, 2013 posting where I outline the situation (which I suspect hasn’t changed much since),

As for the short supply mentioned in the first line of the news item, the world’s largest exporter of rare earth elements at 90% of the market, China, recently announced a cap according to a Sept. 6, 2013 article by David Stanway for Reuters. The Chinese government appears to be curtailing exports as part of an ongoing, multi-year strategy. Here’s how Cientifica‘s (an emerging technologies consultancy, etc.) white paper (Simply No Substitute?) about critical materials published in 2012 (?), described the situation,

Despite their name, REE are not that rare in the Earth’s crust. What has happened in the past decade is that REE exports from China undercut prices elsewhere, leading to the closure of mines such as the Mountain Pass REE mine in California. Once China had acquired a dominant market position, prices began to rise. But this situation will likely ease. The US will probably begin REE production from the Mountain Pass mine later in 2012, and mines in other countries are expected to start operation soon as well.

Nevertheless, owing to their broad range of uses REE will continue to exert pressures on their supply – especially for countries without notable REE deposits. This highlights two aspects of importance for strategic materials: actual rarity and strategic supply issues such as these seen for REE. Although strategic and diplomatic supply issues may have easier solutions, their consideration for manufacturing industries will almost be the same – a shortage of crucial supply lines.

Furthermore, as the example of REE shows, the identification of long-term supply problems can often be difficult, and not every government has the same strategic foresight that the Chinese demonstrated. And as new technologies emerge, new elements may see an unexpected, sudden demand in supply. (pp. 16-17)

Meanwhile, in response to China’s decision to cap its 2013 REE exports, the Russian government announced a $1B investment to 2018 in rare earth production,, according to a Sept. 10, 2013 article by Polina Devitt for Reuters.

I’m not sure you’ll be able to access Tim Harper’s white paper as he is now an independent, serial entrepreneur. I most recently mentioned him in relation to his articles (on Azonano) about the nanotechnology scene in a Feb. 12, 2015 posting where you’ll also find contact details for him.

The quantum chemistry of nanomedicines

A Jan. 29, 2015 news item on Nanowerk provides an overview of the impact quantum chemical reactions may have on nanomedicines. Intriguingly, this line of query started with computations of white dwarf stars,

Quantum chemical calculations have been used to solve big mysteries in space. Soon the same calculations may be used to produce tomorrow’s cancer drugs.

Some years ago research scientists at the University of Oslo in Norway were able to show that the chemical bonding in the magnetic fields of small, compact stars, so-called white dwarf stars, is different from that on Earth. Their calculations pointed to a completely new bonding mechanism between two hydrogen atoms. The news attracted great attention in the media. The discovery, which in fact was made before astrophysicists themselves observed the first hydrogen molecules in white dwarf stars, was made by UiO’s Centre for Theoretical and Computational Chemistry. They based their work on accurate quantum chemical calculations of what happens when atoms and molecules are exposed to extreme conditions.

A Jan. 29, 2015 University of Oslo press release by Yngve Vogt, which originated the news item, offers a substantive description of molecules, electrons, and more for those of us whose last chemistry class is lost in the mists of time,

The research team is headed by Professor Trygve Helgaker, who for the last thirty years has taken the international lead on the design of a computer system for calculating quantum chemical reactions in molecules.

Quantum chemical calculations are needed to explain what happens to the electrons’ trajectories within a molecule.

Consider what happens when UV radiation sends energy-rich photons into your cells. This increases the energy level of the molecules. The outcome may well be that some of the molecules break up. This is exactly what happens when you sun-bathe.

“The extra energy will affect the behaviour of electrons and can destroy the chemical bonding within the molecule. This can only be explained by quantum chemistry. The quantum chemical models are used to produce a picture of the forces and tensions at play between the atoms and the electrons of a molecule, and of what is required for a molecule to dissociate,” says Trygve Helgaker.

The absurd world of the electrons

The quantum chemical calculations solve the Schrödinger equation for molecules. This equation is fundamental to all chemistry and describes the whereabouts of all electrons within a molecule. But here we need to pay attention, for things are really rather more complicated than that. Your high school physics teacher will have told you that electrons circle the atom. Things are not that simple, though, in the world of quantum physics. Electrons are not only particles, but waves as well. The electrons can be in many places at the same time. It’s impossible to keep track of their position. However, there is hope. Quantum chemical models describe the electrons’ statistical positions. In other words, they can establish the probable location of each electron.

The results of a quantum chemical calculation are often more accurate than what is achievable experimentally.

Among other things, the quantum chemical calculations can be used to predict chemical reactions. This means that the chemists will no longer have to rely on guesstimates in the lab. It is also possible to use quantum chemical calculations in order to understand what happens in experiments.

Enormous calculations

The calculations are very demanding.

“The Schrödinger equation is a highly complicated, partial differential equation, which cannot be accurately solved. Instead, we need to make do with heavy simulations”, says researcher Simen Kvaal.

The computations are so demanding that the scientists use one of the University’s fastest supercomputers.

“We are constantly stretching the boundaries of what is possible. We are restricted by the available machine capacity,” explains Helgaker.

Ten years ago it took two weeks to carry out the calculations for a molecule with 140 atoms. Now it can be done in two minutes.

“That’s 20,000 times faster than ten years ago. The computation process is now running 200 times faster because the computers have been doubling their speed every eighteen months. And the process is a further 100 times faster because the software has been undergoing constant improvement,” says senior engineer Simen Reine.

This year the research group has used 40 million CPU hours, of which twelve million were on the University’s supercomputer, which is fitted with ten thousand parallel processors. This allows ten thousand CPU hours to be over and done with in 60 minutes.

“We will always fill the computer’s free capacity. The higher the computational capacity, the bigger and more reliable the calculations.”

Thanks to ever faster computers, the quantum chemists are able to study ever larger molecules.

Today, it’s routine to carry out a quantum chemical calculation of what happens within a molecule of up to 400 atoms. By using simplified models it is possible to study molecules with several thousand atoms. This does, however, mean that some of the effects within the molecule are not being described in detail.

The researchers are now getting close to a level which enables them to study the quantum mechanics of living cells.

“This is exciting. The molecules of living cells may contain many hundred thousand atoms, but there is no need to describe the entire molecule using quantum mechanical principles. Consequently, we are already at a stage when we can help solve biological problems.”

There’s more from the press release which describes how this work could be applied in the future,

Hunting for the electrons of the insulin molecule

The chemists are thus able to combine sophisticated models with simpler ones. “This will always be a matter of what level of precision and detail you require. The optimal approach would have been to use the Schrödinger equation for everything.”

By way of compromise they can give a detailed description of every electron in some parts of the model, while in other parts they are only looking at average numbers.

Simen Reine has been using the team’s computer program, while working with Aarhus University [Finland], on a study of the insulin molecule. An insulin molecule consists of 782 atoms and 3,500 electrons.

“All electrons repel each other, while at the same time being pulled towards the atomic nuclei. The nuclei also repel each other. Nevertheless, the molecule remains stable. In order to study a molecule to a high level of precision, we therefore need to consider how all of the electrons move relative to one another. Such calculations are referred to as correlated and are very reliable.”

A complete correlated calculation of the insulin molecule takes nearly half a million CPU hours. If they were given the opportunity to run the program on the entire University’s supercomputer, the calculations would theoretically take two days.

“In ten years, we’ll be able to make these calculations in two minutes.”

Medically important

“Quantum chemical calculations can help describe phenomena at a level that may be difficult to access experimentally, but may also provide support for interpreting and planning experiments. Today, the calculations will be put to best use within the fields of molecular biology and biochemistry,” says Knut Fægri [vice-rector at the University of Oslo].

“Quantum chemistry is a fundamental theory which is important for explaining molecular events, which is why it is essential to our understanding of biological systems,” says [Associate Professor] Michele Cascella.

By way of an example, he refers to the analysis of enzymes. Enzymes are molecular catalysts that boost the chemical reactions within our cells.

Cascella also points to nanomedicines, which are drugs tasked with distributing medicine round our bodies in a much more accurate fashion.

“In nanomedicine we need to understand physical phenomena on a nano scale, forming as correct a picture as possible of molecular phenomena. In this context, quantum chemical calculations are important,” explains Michele Cascella.

Proteins and enzymes

Professor K. Kristoffer Andersson at the Department of Biosciences uses the simpler form of quantum chemical calculations to study the details of protein structures and the chemical atomic and electronic functions of enzymes.

“It is important to understand the chemical reaction mechanism, and how enzymes and proteins work. Quantum chemical calculations will teach us more about how proteins go about their tasks, step by step. We can also use the calculations to look at activation energy, i.e. how much energy is required to reach a certain state. It is therefore important to understand the chemical reaction patterns in biological molecules in order to develop new drugs,” says Andersson.

His research will also be useful in the search for cancer drugs. He studies radicals, which may be important to cancer. Among other things, he is looking at the metal ions function in proteins. These are ions with a large number of protons, neutrons and electrons.


Professor Einar Uggerud at the Department of Chemistry has uncovered an entirely new form of chemical bonding through sophisticated experiments and quantum chemical calculations.

Working with research fellow Glenn Miller, Professor Uggerud has found an unusually fragile key molecule, in a kite-shaped structure, consisting of magnesium, carbon and oxygen. The molecule may provide a new understanding of photosynthesis. Photosynthesis, which forms the basis for all life, converts CO2 into sugar molecules.

The molecule reacts so fast with water and other molecules that it has only been possible to study in isolation from other molecules, in a vacuum chamber.

“Time will tell whether the molecule really has an important connection with photosynthesis,” says Einar Uggerud.

I’m delighted with this explanation as it corrects my understanding of chemical bonds and helps me to better understand computational chemistry. Thank you University of Oslo and Yngve Vogt.

Finally, here’s a representation of an insulin molecule as understood by quantum computation,


INSULIN: Working with Aarhus University, Simen Reine has calculated the tensions between the electrons and atoms of an insulin molecule. An insulin molecule consists of 782 atoms and 3,500 electrons. Illustration: Simen Reine-UiO


Replacing copper wire in motors?

Finnish researchers at Lappeenranta University of Technology (LUT) believe it may be possible to replace copper wire used in motors with spun carbon nanotubes. From an Oct. 15, 2014 news item on Azonano,

Lappeenranta University of Technology (LUT) introduces the first electrical motor applying carbon nanotube yarn. The material replaces copper wires in windings. The motor is a step towards lightweight, efficient electric drives. Its output power is 40 W and rotation speed 15000 rpm.

Aiming at upgrading the performance and energy efficiency of electrical machines, higher-conductivity wires are searched for windings. Here, the new technology may revolutionize the industry. The best carbon nanotubes (CNTs) demonstrate conductivities far beyond the best metals; CNT windings may have double the conductivity of copper windings.

”If we keep the design parameters unchanged only replacing copper with carbon nanotube yarns, the Joule losses in windings can be reduced to half of present machine losses. By lighter and more ecological CNT yarn, we can reduce machine dimensions and CO2 emissions in manufacturing and operation. Machines could also be run in higher temperatures,” says Professor Pyrhönen [Juha Pyrhönen], leading the prototype design at LUT.

An Oct. ??, 2014 (?) LUT press release, which originated the news item, further describes the work,

Traditionally, the windings in electrical machines are made of copper, which has the second best conductivity of metals at room temperature. Despite the high conductivity of copper, a large proportion of the electrical machine losses occur in the copper windings. For this reason, the Joule losses are often referred to as copper losses. The carbon nanotube yarn does not have a definite upper limit for conductivity (e.g. values of 100 MS/m have already been measured).

According to Pyrhönen, the electrical machines are so ubiquitous in everyday life that we often forget about their presence. In a single-family house alone there can be tens of electrical machines in various household appliances such as refrigerators, washing machines, hair dryers, and ventilators.

“In the industry, the number of electrical motors is enormous: there can be up to tens of thousands of motors in a single process industry unit. All these use copper in the windings. Consequently, finding a more efficient material to replace the copper conductors would lead to major changes in the industry,” tells Professor Pyrhönen.

There are big plans for this work according to the press release,

The prototype motor uses carbon nanotube yarns spun and converted into an isolated tape by a Japanese-Dutch company Teijin Aramid, which has developed the spinning technology in collaboration with Rice University, the USA. The industrial applications of the new material are still in their infancy; scaling up the production capacity together with improving the yarn performance will facilitate major steps in the future, believes Business Development Manager Dr. Marcin Otto from Teijin Aramid, agreeing with Professor Pyrhönen.

“There is a significant improvement potential in the electrical machines, but we are now facing the limits of material physics set by traditional winding materials. Superconductivity appears not to develop to such a level that it could, in general, be applied to electrical machines. Carbonic materials, however, seem to have a pole position: We expect that in the future, the conductivity of carbon nanotube yarns could be even three times the practical conductivity of copper in electrical machines. In addition, carbon is abundant while copper needs to be mined or recycled by heavy industrial processes.”

The researchers have produced this video about their research,

There’s a reference to some work done at Rice University (Texas, US) with Teijin Armid (Japanese-Dutch company) and Technion Institute (Israel) with spinning carbon nanotubes into threads that look like black cotton (you’ll see the threads in the video). It’s this work that has made the latest research in Finland possible. I have more about the the Rice/Teijin Armid/Technion CNT project in my Jan. 11, 2013 posting, Prima donna of nanomaterials (carbon nanotubes) tamed by scientists at Rice University (Texas, US), Teijin Armid (Dutch/Japanese company), and Technion Institute (based in Israel).

‘Scotch-tape’ technique for isolating graphene

The ‘scotch-tape’ technique is mythologized in the graphene origins story which has scientists, Andre Geim and Konstantin Novoselov, first isolating the material by using adhesive (aka ‘sticky’ tape or ‘scotch’ tape) as per my Oct. 7, 2010 posting,

The technique that Geim and Novoselov used to create the first graphene sheets both amuses and fascinates me (from the article by Kit Eaton on the Fast Company website),

The two scientists came up with the technique that first resulted in samples of graphene–peeling individual atoms-deep sheets of the material from a bigger block of pure graphite. The science here seems almost foolishly simple, but it took a lot of lateral thinking to dream up, and then some serious science to investigate: Geim and Novoselo literally “ripped” single sheets off the graphite by using regular adhesive tape. Once they’d confirmed they had grabbed micro-flakes of the material, Geim and Novoselo were responsible for some of the very early experiments into the material’s properties. Novel stuff indeed, but perhaps not so unexpected from a scientist (Geim) who the Nobel Committe notes once managed to make a frog levitate in a magnetic field.

A May 21, 2014 article about Geim who has won both a Nobel and an Ig Nobel (the only scientist to do so) and graphene by Sarah Lewis for Fast Company offers more details about the discovery,

The graphene FNE [Friday Night Experiments] began when Geim asked Da Jiang, a doctoral student from China, to polish a piece of graphite an inch across and a few millimeters thick down to 10 microns using a specialized machine. Partly due to a language barrier, Jiang polished the graphite down to dust, but not the ultimate thinness Geim wanted.

Helpfully, the Geim lab was also observing graphite using scanning tunneling microscopy (STM). The experimenters would clean the samples beforehand using Scotch tape, which they would then discard. “We took it out of the trash and just used it,” Novoselov said. The flakes of graphite on the tape from the waste bin were finer and thinner than what Jiang had found using the fancy machine. They weren’t one layer thick—that achievement came by ripping them some more with Scotch tape.

They swapped the adhesive for Japanese Nitto tape, “probably because the whole process is so simple and cheap we wanted to fancy it up a little and use this blue tape,” Geim said. Yet “the method is called the ‘Scotch tape technique.’ I fought against this name, but lost.”

Scientists elsewhere have been inspired to investigate the process in minute detail as per a June 27, 2014 news item on Nanowerk,

The simplest mechanical cleavage technique using a primitive “Scotch” tape has resulted in the Nobel-awarded discovery of graphenes and is currently under worldwide use for assembling graphenes and other two-dimensional (2D) graphene-like structures toward their utilization in novel high-performance nanoelectronic devices.

The simplicity of this method has initiated a booming research on 2D materials. However, the atomistic processes behind the micromechanical cleavage have still been poorly understood.

A June 27, 2014 MANA (International Center for Materials Nanoarchitectoinics) news release, which originated the news item, provides more information,

A joined team of experimentalists and theorists from the International Center for Young Scientists, International Center for Materials Nanoarchitectonics and Surface Physics and Structure Unit of the National Institute for Materials Science, National University of Science and Technology “MISiS” (Moscow, Russia), Rice University (USA) and University of Jyväskylä (Finland) led by Daiming Tang and Dmitri Golberg for the first time succeeded in complete understanding of physics, kinetics and energetics behind the regarded “Scotch-tape” technique using molybdenum disulphide (MoS2) atomic layers as a model material.

The researchers developed a direct in situ probing technique in a high-resolution transmission electron microscope (HRTEM) to investigate the mechanical cleavage processes and associated mechanical behaviors. By precisely manipulating an ultra-sharp metal probe to contact the pre-existing crystalline steps of the MoS2 single crystals, atomically thin flakes were delicately peeled off, selectively ranging from a single, double to more than 20 atomic layers. The team found that the mechanical behaviors are strongly dependent on the number of layers. Combination of in situ HRTEM and molecular dynamics simulations reveal a transformation of bending behavior from spontaneous rippling (< 5 atomic layers) to homogeneous curving (~ 10 layers), and finally to kinking (20 or more layers).

By considering the force balance near the contact point, the specific surface energy of a MoS2 monoatomic layer was calculated to be ~0.11 N/m. This is the first time that this fundamentally important property has directly been measured.

After initial isolation from the mother crystal, the MoS2 monolayer could be readily restacked onto the surface of the crystal, demonstrating the possibility of van der Waals epitaxy. MoS2 atomic layers could be bent to ultimate small radii (1.3 ~ 3.0 nm) reversibly without fracture. Such ultra-reversibility and extreme flexibility proves that they could be mechanically robust candidates for the advanced flexible electronic devices even under extreme folding conditions.

Here’s a link to and a citation for the research paper,

Nanomechanical cleavage of molybdenum disulphide atomic layers by Dai-Ming Tang, Dmitry G. Kvashnin, Sina Najmaei, Yoshio Bando, Koji Kimoto, Pekka Koskinen, Pulickel M. Ajayan, Boris I. Yakobson, Pavel B. Sorokin, Jun Lou, & Dmitri Golberg. Nature Communications 5, Article number: 3631 doi:10.1038/ncomms4631 Published 03 April 2014

This paper is behind a paywall but there is a free preview available through ReadCube Access.