Tag Archives: Rice University

Tracking gas, oil, and, possibly, water in wells

A Feb. 24, 2014 Rice University news release (also on EurekAlert) and on Azonano as a Feb. 25, 2014 news item) describes a technique tracks which wells are producing oil or gas in fracking operations,

A tabletop device invented at Rice University can tell how efficiently a nanoparticle would travel through a well and may provide a wealth of information for oil and gas producers.

The device gathers data on how tracers – microscopic particles that can be pumped into and recovered from wells – move through deep rock formations that have been opened by hydraulic fracturing [fracking].

Here’s an image of two Rice scientists playing around with a prototype of their tabletop device,

Rice University chemist Andrew Barron and graduate student Brittany Oliva-Chatelain investigate the prototype of a device that allows for rapid testing of nanotracers for the evaluation of wells subject to hydraulic fracturing. (Credit: Jeff Fitlow/Rice University)

Rice University chemist Andrew Barron and graduate student Brittany Oliva-Chatelain investigate the prototype of a device that allows for rapid testing of nanotracers for the evaluation of wells subject to hydraulic fracturing. (Credit: Jeff Fitlow/Rice University)

The news release goes on to describe the fracking process and explain why the companies don’t know which well is actually producing (Note: Links have been removed),

Drilling companies use fracturing to pump oil and gas from previously unreachable reservoirs. Fluids are pumped into a wellbore under high pressure to fracture rocks, and materials called “proppants,” like sand or ceramic, hold the fractures open. “They’re basically making a crack in the rock and filling it with little beads,” said Rice chemist Andrew Barron, whose lab produced the device detailed in the Royal Society of Chemistry journal Environmental Science Processes and Impacts.

But the companies struggle to know which insertion wells — where fluids are pumped in — are connected to the production wells where oil and gas are pumped out. “They may be pumping down three wells and producing from six, but they have very little idea of which well is connected to which,” he said.

Tracer or sensor particles added to fracturing fluids help solve that problem, but there’s plenty of room for optimization, especially in minimizing the volume of nanoparticles used now, he said. “Ideally, we would take a very small amount of a particle that does not interact with proppant, rock or the gunk that’s been pumped downhole, inject it in one well and collect it at the production well. The time it takes to go from one to the other will tell you about the connectivity underground.”

Barron explained the proppant itself accounts for most of the surface area the nanoparticles encounter, so it’s important to tune the tracers to the type of proppant used.

He said the industry lacks a uniform method to test and optimize custom-designed nanoparticles for particular formations and fluids. The ultimate goal  is to optimize the particles so they don’t clump together or stick to the rock or proppant and can be reliably identified when they exit the production well.

Here’s how the tracers work (from the news release),

The automated device by Barron, Rice alumnus Samuel Maguire-Boyle and their colleagues allows them to run nanotracers through a small model of a geological formation and quickly analyze what comes out the other side.

The device sends a tiny amount of silver nanoparticle tracers in rapid pulses through a solid column, simulating the much longer path the particles would travel in a well. That gives the researchers an accurate look at both how sticky and how robust the particles are.

“We chose silver nanoparticles for their plasmon resonance,” Barron said. “They’re very easy to see (with a spectroscope) making for high-quality data.” He said silver nanoparticles would be impractical in a real well, but because they’re easy to modify with other useful chemicals, they are good models for custom nanoparticles.

“The process is simple enough that our undergraduates make different nanoparticles and very quickly test them to find out how they behave,” Barron said.

The method also shows promise for tracking water from source to destination, which could be valuable for government agencies that want to understand how aquifers are linked or want to trace the flow of elements like pollutants in a water supply, he said.

Barron said the Rice lab won’t oversee production of the test rig, but it doesn’t have to. “We just published the paper, but if companies want to make their own, it includes the instructions. The supplementary material is basically a manual for how to do this,” he said.

You can find the paper with this link and/or citation,

Automated method for determining the flow of surface functionalized nanoparticles through a hydraulically fractured mineral formation using plasmonic silver nanoparticles by Samuel J. Maguire-Boyle, David J. Garner, Jessica E. Heimann, Lucy Gao, Alvin W. Orbaek, and Andrew R. Barron. Environ. Sci.: Processes Impacts, 2014,16, 220-231 DOI: 10.1039/C3EM00718A First published online 07 Jan 2014

This paper has been published in one of the Royal Society’s open access journals.

My final note, one of my more recent posts about fracking highlights some research that was taking place in Texas (Rice University’s home state) at Texas A&M University, see my July 29, 2013 posting.

Control the chirality, control your carbon nanotube

A Feb. 18, 2014 news item on ScienceDaily features a story not about a breakthrough but about a discovery that* could lead to one,

A single-walled carbon nanotube grows from the round cap down, so it’s logical to think the cap’s formation determines what follows. But according to researchers at Rice University, that’s not entirely so.

Theoretical physicist Boris Yakobson and his Rice colleagues found through exhaustive analysis that those who wish to control the chirality of nanotubes — the characteristic that determines their electrical properties — would be wise to look at other aspects of their growth.

The scientists have provided this image to illustrate chirality (‘twisting’) in carbon nanotubes,

Carbon nanotube caps are forced into shape by six pentagons among the array of hexagons in the single-atom-thick tube. Rice University researchers took a census of thousands of possible caps and found the energies dedicated to their formation have no bearing on the tube's ultimate chirality. Credit: Evgeni Penev/Rice University

Carbon nanotube caps are forced into shape by six pentagons among the array of hexagons in the single-atom-thick tube. Rice University researchers took a census of thousands of possible caps and found the energies dedicated to their formation have no bearing on the tube’s ultimate chirality.
Credit: Evgeni Penev/Rice University

The Feb. 17, 2014 Rice University news release (also on EurekAlert), which originated the news item, describe the process the scientists used to research chirality in carbon nanotubes,

To get a clear picture of how caps are related to nanotube chirality, the Rice group embarked upon a detailed, two-year census of the 4,500 possible cap formations for nanotubes of just two diameters, 0.8 and 1 nanometer, across 21 chiralities.

The cap of every nanotube has six pentagons – none of which may touch each other — among an array of hexagons, Penev said. They pull the cap and force it to curve, but their positions are not always the same from cap to cap.

But because a given chirality can have hundreds of possible caps, the determining factor for chirality must lie elsewhere, the researchers found. “The contribution of the cap is the elastic curvature energy, and then you just forget it,” Penev said.

“There are different factors that may be in play,” Yakobson said. “One is the energy portion dictated by the catalyst; another one may be the energy of the caps per se. So to get the big picture, we address the energy of the caps and basically rule it out as a factor in determining chirality.”

A nanotube is an atom-thick sheet of carbon atoms arranged in hexagons and rolled into a tube. Chirality refers to the hexagons’ orientation, and that angle controls how well the nanotube will conduct electricity.

A perfect conducting metallic nanotube would have the atoms arranged in “armchairs,” so-called because cutting the nanotube in half would make the top look like a series of wells with atoms for armrests. Turn the hexagons 30 degrees, though, will make a semiconducting “zigzag” nanotube.  Nanotubes can be one or the other, or the chiral angle can be anything in between, with a shifting range of electrical properties.

Getting control of these properties has been a struggle. Ideally, scientists could grow the specific kinds of nanotubes they need for an application, but in reality, they grow as a random assortment that must then be separated with a centrifuge or by other means.

Yakobson suspects the answer lies in tuning the interaction between the catalyst and the nanotube edge. “This study showed the energy involved in configuring the cap is reasonably flat,” he said. “That’s important to know because it allows us to continue to work on other factors.

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

Extensive Energy Landscape Sampling of Nanotube End-Caps Reveals No Chiral-Angle Bias for Their Nucleation by Evgeni S. Penev, Vasilii I. Artyukhov, and Boris I. Yakobson. ACS Nano, Article ASAP DOI: 10.1021/nn406462e Publication Date (Web): January 23, 2014
Copyright © 2014 American Chemical Society

This article is behind a paywall.

One final comment, it took these scientists two years of painstaking work to establish that caps are not the determining factor for chirality. It’s this type of story I find as fascinating, if not more so, as the big breakthroughs because it illustrates the  extraordinary drive it takes to extract even the smallest piece of information. I wish more attention was given to these incremental efforts.

* March 7, 2014 changed ‘while’ to ‘that’.

Quadruple the amount of electrical current by using carbon nanotube-based fibers

The announcement from Rice University was written in an interesting fashion. The good news is that you can quadruple the amount of electrical current being carried by substituting copper with carbon nanotube-based fibers. Unfortunately, expectations are set for a much higher rate before the good news is revealed in this Feb.  14, 2013 news item on ScienceDaily,

On a pound-per-pound basis, carbon nanotube-based fibers invented at Rice University have greater capacity to carry electrical current than copper cables of the same mass, according to new research.

While individual nanotubes are capable of transmitting nearly 1,000 times more current than copper, the same tubes coalesced into a fiber using other technologies fail long before reaching that capacity.

But a series of tests at Rice showed the wet-spun carbon nanotube fiber still handily beat copper, carrying up to four times as much current as a copper wire of the same mass. [emphasis mine]

That, said the researchers, makes nanotube-based cables an ideal platform for lightweight power transmission in systems where weight is a significant factor, like aerospace applications.

The Feb. 13, 2014 Rice University news release (dated as Feb. 14, 2014 on EurekAlert), which originated the news item, provides context for this discovery (Note: Links have been removed),

The analysis led by Rice professors Junichiro Kono and Matteo Pasquali appeared online this week [week of Feb. 10 - 14, 2014] in the journal Advanced Functional Materials. Just a year ago [2013] the journal Science reported that Pasquali’s lab, in collaboration with scientists at the Dutch firm Teijin Aramid, created a very strong conductive fiber out of carbon nanotubes.

Present-day transmission cables made of copper or aluminum are heavy because their low tensile strength requires steel-core reinforcement.

Scientists working with nanoscale materials have long thought there’s a better way to move electricity from here to there. Certain types of carbon nanotubes can carry far more electricity than copper. The ideal cable would be made of long metallic “armchair” nanotubes that would transmit current over great distances with negligible loss, but such a cable is not feasible because it’s not yet possible to manufacture pure armchairs in bulk, Pasquali said.

I have a couple of notes (1) the 2013 work on ‘armchair’ carbon nanotubes was featured here in a Feb. 6, 2013 posting and (2) Teijin Aramid is located in the Netherlands while its parent company, Teijin, is located in Japan (you can find more about Teijin in this Wikipedia essay).

Getting back to this latest work from Rice (from the news release),

In the meantime, the Pasquali lab has created a method to spin fiber from a mix of nanotube types that still outperforms copper. The cable developed by Pasquali and Teijin Aramid is strong and flexible even though at 20 microns wide, it’s thinner than a human hair.

Pasquali turned to Kono and his colleagues, including lead author Xuan Wang, a postdoctoral researcher at Rice, to quantify the fiber’s capabilities.

Pasquali said there has been a disconnect between electrical engineers who study the current carrying capacity of conductors and materials scientists working on carbon nanotubes. “That has generated some confusion in the literature over the right comparisons to make,” he said. “Jun and Xuan really got to the bottom of how to do these measurements well and compare apples to apples.”

The researchers analyzed the fiber’s “current carrying capacity” (CCC), or ampacity, with a custom rig that allowed them to test it alongside metal cables of the same diameter. The cables were tested while they were suspended in the open air, in a vacuum and in nitrogen or argon environments.

Electric cables heat up because of resistance. When the current load exceeds the cable’s safe capacity, they get too hot and break. The researchers found nanotube fibers exposed to nitrogen performed best, followed by argon and open air, all of which were able to cool through convection. The same nanotube fibers in a vacuum could only cool by radiation and had the lowest CCC.

“The outcome is that these fibers have the highest CCC ever reported for any carbon-based fibers,” Kono said. “Copper still has better resistivity by an order of magnitude, but we have the advantage that carbon fiber is light. So if you divide the CCC by the mass, we win.”

Kono plans to further investigate and explore the fiber’s multifunctional aspects, including flexible optoelectronic device applications.

Pasquali suggested the thread-like fibers are light enough to deliver power to aerial vehicles. “Suppose you want to power an unmanned aerial vehicle from the ground,” he mused. “You could make it like a kite, with power supplied by our fibers. I wish Ben Franklin were here to see that!”

Pasquali and his team’s latest research can be found here,

High-Ampacity Power Cables of Tightly-Packed and Aligned Carbon Nanotubes by Xuan Wang, Natnael Behabtu, Colin C. Young, Dmitri E. Tsentalovich, Matteo Pasqua, & Junichiro Kono. Advanced Functional Materials, Article first published online: 13 FEB 2014 DOI: 10.1002/adfm.201303865

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This study is behind a paywall.

Diamane—a no pressure road map

Russian and US researchers have produced a road map for creating ‘diamane’, according to a Feb. 3, 2014  Rice University (Texas) news release (available on EurekAlert and also as a Feb. 4, 2014 news item on Azonano),

Perfect sheets of diamond a few atoms thick appear to be possible even without the big squeeze that makes natural gems.

Scientists have speculated about it and a few labs have even seen signs of what they call diamane, an extremely thin film of diamond that has all of diamond’s superior semiconducting and thermal properties.

Now researchers at Rice University and in Russia have calculated a “phase diagram” for the creation of diamane. The diagram is a road map. It lays out the conditions – temperature, pressure and other factors – that would be necessary to turn stacked sheets of graphene into a flawless diamond lattice.

In the process, the researchers determined diamane could be made completely chemically, with no pressure at all, under some circumstances.

The news release provides more into the researchers’ theories and road map,

“Diamanes have a wide potential range of application,” Sorokin [Pavel Sorokin, a former postdoctoral associate at Rice and now a senior researcher at the Technological Institute for Superhard and Novel Carbon Materials in Moscow] said. “They can be applied as very thin, dielectric hard films in nanocapacitors or mechanically stiff, nanothick elements in nanoelectronics. Also, diamanes have potential for application in nano-optics.

“The possibility of obtaining such a quasi-two-dimensional object is intriguing, but available experimental data prevents the expectation of its fabrication using traditional methods. However, the ‘bottom-up’ approach proposed by Richard Feynman allows the fabrication of diamanes from smaller objects, such as graphene.”

The researchers built computer models to simulate the forces applied by every atom involved in the process. That includes the graphene, the single-atom-thick form of carbon and one of the strongest substances in the universe, as well as the hydrogen (or, alternately, a halogen) that promotes the reaction.

Conditions, they learned, need to be just right for a short stack of graphene pancakes to collapse into a diamond matrix – or vice versa – via chemistry.

“A phase diagram shows you which phase dominates the ground state for each pressure and temperature,” Yakobson [Rice theoretical physicist Boris Yakobson] said. “In the case of diamane, the diagram is unusual because the result also depends on thickness, the number of layers of graphene. So we have a new parameter.”

Hydrogen isn’t the only possible catalyst, he said, but it’s the one they used in their calculations. “When the hydrogen attacks, it takes one electron from a carbon atom in graphene. As a result, a bond is broken and another electron is left hanging on the other side of the graphene layer. It’s now free to connect to a carbon atom on the adjacent sheet with little or no pressure.

“If you have several layers, you get a domino effect, where hydrogen starts a reaction on top and it propagates through the bonded carbon system,” he said. “Once it zips all the way through, the phase transition is complete and the crystal structure is that of diamond.”

Yakobson said the paper doesn’t cover a possible deal-breaker. “The conversion from one phase to another starts from a small seed, a nucleation site, and in this process there’s always what is called a nucleation barrier. We don’t calculate that here.” He said carbon normally prefers to be graphite (the bulk form of carbon used as pencil lead) rather than diamond, but a high nucleation barrier prevents diamond from making the transition.

“Thermodynamically, an existing diamond should become graphite, but it doesn’t happen for exactly this reason,” Yakobson said. “So sometimes it’s a good thing. But if we want to make flat diamond, we need to find ways to circumvent this barrier.”

He said the manufacture of synthetic diamond, which was first reliably made in the 1950s, requires very high pressures of about 725,000 pounds per square inch. Manufactured diamonds are used in hardened tools for cutting, as abrasives and even as high-quality gemstones grown via techniques that simulate the temperatures and pressures found deep in Earth, where natural diamond is forged.

Diamond films are also routinely made via chemical vapor deposition, “but they’re always very poor quality because they’re polycrystalline,” Yakobson said. “For mechanical purposes, like very expensive sandpaper, they’re perfect. But for electronics, you would need high quality for it to serve as a wide-band gap semiconductor.”

This image illustrates the conditions necessary to create diamane,

The phase diagram developed by scientists at Rice University and in Moscow describes the conditions necessary for the chemical creation of thin films of diamond from stacks of single-atomic-layer graphene. (Credit: Pavel Sorokin/Technological Institute for Superhard and Novel Carbon Materials)

The phase diagram developed by scientists at Rice University and in Moscow describes the conditions necessary for the chemical creation of thin films of diamond from stacks of single-atomic-layer graphene. (Credit: Pavel Sorokin/Technological Institute for Superhard and Novel Carbon Materials)

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

Phase Diagram of Quasi-Two-Dimensional Carbon, From Graphene to Diamond by Alexander G. Kvashnin, Leonid A. Chernozatonskii, Boris I. Yakobson, and Pavel B. Sorokin. Nano Lett., Article ASAP DOI: 10.1021/nl403938g Publication Date (Web): January 17, 2014
Copyright © 2014 American Chemical Society

This paper is behind a paywall.

Rice University (Texas) researchers ‘soften’ a buckyball (buckminster fullerene)

A Jan. 16, 2014 Rice University news release landed in my mailbox this morning and revealed that researchers have ‘detuned’ or softened the atomic bonks in a molecule known as a buckminster fullenere (aka, buckyball),

Rice University scientists have found they can control the bonds between atoms in a molecule.

The molecule in question is carbon-60, also known as the buckminsterfullerene and the buckyball, discovered at Rice in 1985. The scientists led by Rice physicists Yajing Li and Douglas Natelson found that it’s possible to soften the bonds between atoms by applying a voltage and running an electric current through a single buckyball.

“This doesn’t mean we’re going to be able to arbitrarily dial around the strength of materials or anything like that,” Natelson said. “This is a very specific case, and even here it was something of a surprise to see this going on.

“But in general, if we can manipulate the charge distribution on molecules, we can affect their vibrations. We can start thinking, in the future, about controlling things in a better way.”

The effect appears when a buckyball attaches to a gold surface in the optical nano antenna used to measure the effects of an electric current on intermolecular bonds through a technique called Raman spectroscopy.

Natelson’s group built the nano antenna a few years ago to trap small numbers of molecules in a nanoscale gap between gold electrodes. Once the molecules are in place, the researchers can chill them, heat them, blast them with energy from a laser or electric current and measure the effect through spectroscopy, which gathers information from the frequencies of light emitted by the object of interest.

With continuing refinement, the researchers found they could analyze molecular vibrations and the bonds between the atoms in the molecule. That ability led to this experiment, Natelson said.

Natelson compared the characteristic vibrational frequencies exhibited by the bonds to the way a guitar string vibrates at a specific frequency based on how tightly it’s wound. Loosen the string and the vibration diminishes and the tone drops.

The nano antenna is able to detect the “tone” of detuned vibrations between atoms through surface-enhanced Raman spectroscopy (SERS), a technique that improves the readings from molecules when they’re attached to a metal surface. Isolating a buckyball in the gap between the gold electrodes lets the researchers track vibrations through the optical response seen via SERS.

When a buckyball attaches to a gold surface, its internal bonds undergo a subtle shift as electrons at the junction rearrange themselves to find their lowest energetic states. The Rice experiment found the vibrations in all the bonds dropped ever so slightly in frequency to compensate.

“Think of these molecules as balls and springs,” Natelson said. “The atoms are the balls and the bonds that hold them together are the springs. If I have a collection of balls and springs and I smack it, it would show certain vibrational modes.

“When we push current through the molecule, we see these vibrations turn on and start to shake,” Natelson said. “But we found, surprisingly, that the vibrations in buckyballs get softer, and by a significant amount. It’s as if the springs get floppier at high voltages in this particular system.” The effect is reversible; turn off the juice and the buckyball goes back to normal, he said.

The researchers used a combination of experimentation and sophisticated theoretical calculations to disprove an early suspicion that the well-known vibrational Stark effect was responsible for the shift. The Stark effect is seen when molecules’ spectral responses shift under the influence of an electric field. The Molecular Foundry, a Department of Energy User Facility at Lawrence Berkeley National Laboratory, collaborated on the calculations component.

Natelson’s group had spied similar effects on oligophenylene vinylene molecules used in previous experiments, also prompting the buckyball experiments. “A few years ago we saw hints of vibrational energies moving around, but nothing this clean or this systematic. It does seem like C-60 is kind of special in terms of where it sits energetically,” he said.

The discovery of buckyballs, which earned a Nobel Prize for two Rice professors, kick-started the nanotechnology revolution. “They’ve been studied very well and they’re very chemically stable,” Natelson said of the soccer-ball-shaped molecules. “We know how to put them on surfaces, what you can do to them and have them still be intact. This is all well understood.” He noted other researchers are looking at similar effects through the molecular manipulation of graphene, the single-atomic-layer form of carbon.

“I don’t want to make some grand claim that we’ve got a general method for tuning the molecular bonding in everything,” Natelson said. “But if you want chemistry to happen in one spot, maybe you want to make that bond really weak, or at least make it weaker than it was.

“There’s a long-sought goal by some in the chemistry community to gain precise control over where and when bonds break. They would like to specifically drive certain bonds, make sure certain bonds get excited, make sure certain ones break. We’re offering ways to think about doing that.”

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

Voltage tuning of vibrational mode energies in single-molecule junctions by Yajing Li, Peter Doak, Leeor Kronik, Jeffrey B. Neatonc, and Douglas Natelsona. PNAS.  doi: 10.1073/pnas.1320210111

This paper is behind a paywall so you need either a subscription to the journal or access to a research library with a subscription or, alternatively, there are two short-term rental options (which for reasons that escape me were difficult to access) here.

As business models go, I don’t believe that aspect of the PNAS model is going to prove successful. Why not make all the options available from the page containing the abstract as do other academic publishers?

Getting back to the buckyball, the researchers have provided an image to illustrate their work,

Rice University scientists discovered the bonds in a carbon-60 molecule – a buckyball – can be "detuned" when exposed to an electric current in an optical antenna. (Credit: Natelson Group/Rice University)

Rice University scientists discovered the bonds in a carbon-60 molecule – a buckyball – can be “detuned” when exposed to an electric current in an optical antenna. (Credit: Natelson Group/Rice University)

Crypton and NANO-TEX together at last

A Jan. 6, 2014 news item on Nanowerk notes that Crypton Fabrics has purchased NANO-TEX,

CRYPTON INC. has acquired NANO-TEX®, announced Randy Rubin, Chairman of The Crypton Companies. The privately held, 20-year-old Crypton Fabrics, based in Bloomfield Hills, Michigan, recently purchased NANO-TEX from private equity and venture capital investors; WL Ross and Co. LLC as major stockholders, in addition to Norwest Venture Partners, Masters Capital Nanotechnology Fund, Firelake Capital Management and Masters Capital Management.

NANO-TEX is a textile technology company whose performance finishes have enhanced leading consumer brands such as GAP, TARGET, MAIDENFORM, BASS PRO SHOPS, NORDSTROM, LAND’S END, FISHER-PRICE and many more.

The Jan. 6, 2014 Crypton (there has to be a Superman or inert gas enthusiast in that company) press release, which can be found on this page under this title: Silicon Valley to Motown, Performance Textile Leader Crypton Purchases Nano-Tex, explains why the NANO-TEX acquisition was so attractive and what it means to NANO-TEX’s major stockholders,

NANO‐TEX employs a proprietary nanotechnology approach to enhance textiles at the molecular level that provides permanent performance attributes such as stain and water resistance, moisture wicking, odor control, static elimination and wrinkle free properties. The end result is performance fabrics that maintain the original comfort, look and feel of the fabric and perform for the life of the product.

In 2013, NANO‐TEX technologies were on $280 million in branded finished products at retail worldwide.

Wilbur Ross, Jr., Chairman of WL Ross said, “We are extremely pleased by Crypton’s acquisition. This assures that NANO‐TEX will continue on a strong growth trajectory. Its expanding market reach and prominence will further enhance the competitiveness of WL Ross’s companies in the consumer and industrial fabrics industries, too; the goal that sparked our initial investment interest in NANO‐TEX eight years ago.”

It seems there was a specific product which attracted the Crypton team’s attention,

“This is a strategic acquisition as we extend our market share with apparel throughout the world. The intellectual properties and latest development, Aquapel®, a non‐fluorinated repellency treatment, is very exciting to our research team,” said Rubin.

There’s more about this product on the NANO-TEX Aquapel® page.

On a completely other note, at least one NANO-TEX product has silver in it according to a 2007 entry on the Consumer Products Inventory (Project on Emerging Nanotechnologies),

They Say:

“Nano-Tex™’s revolutionary technology fundamentally transforms fabric at the nano-level to dramatically improve your favorite everyday clothing.”

Nanomaterials:

Silver

Potential Exposure Pathways:

Dermal

How much we know:

Category 4 (Unsupported claim)

Additional Information:

Generic Product

Crypton too has silver in at least one product (from the INCASE Fabric Protection FAQs),

Q:  How does INCASE™ resist bacterial growth?
A: Silver Ion technology is used in INCASE to inhibit the growth of a broad spectrum of medically relevant microorganisms, including bacteria. Silver is one of nature’s original antimicrobials. Used thousands of years ago by Greeks in vessels to preserve water and wine, the natural benefits of silver have now been tapped to keep fabrics odor-free.

Cyrpton’s INCASE product uses sliver ions, which according to some research at Rice University (based in Texas, US), are more toxic than silver nanoparticles, from my July 13, 2012 posting,

He [Pedro Alvarez, George R. Brown Professor and chair of Rice’s Civil and Environmental Engineering Department] said the finding should shift the debate over the size, shape and coating of silver nanoparticles. [emphasis mine] “Of course they matter,” Alvarez said, “but only indirectly, as far as these variables affect the dissolution rate of the ions. The key determinant of toxicity is the silver ions. So the focus should be on mass-transfer processes and controlled-release mechanisms.”

Crypton’s About page strongly suggests an environmentally friendly and health conscious company (Note: Links have been removed),

Innovation. Industry leadership. A deep commitment to product excellence. These core elements are at the heart of the Crypton DNA – a labor of love that began in 1993 when founders Craig and Randy Rubin set out to create a new generation of stylish fabrics that were moisture-resistant and easy-to-clean, yet soft, comfortable and breathable.

From the basement of their Michigan home, a textile revolution was born.

Now based in West Bloomfield Michigan, with a green manufacturing facility in Kings Mountain, North Carolina, Crypton is the only textile solution in the world offering complete stain, moisture, mildew, bacteria and odor-resistant protection thanks to a patented process developed by some of the leading minds in the textile industry.

Early on, by offering a fabric – not a vinyl or plastic – that was capable of resisting stains, moisture, odors and bacteria, Crypton proved to be the perfect solution for the health care market. Following this initial success, Crypton solutions rapidly expanded into some of the finest restaurants, hotels, cruise ships around the world, as well as government complexes, schools and health care facilities.

Now trusted and relied on by over 90% of contract designers, there are more than 20,000 patterns of Crypton fabric available today. Crypton is the only fabric deemed a non-porous surface and can be disinfected when used in conjunction with our U.S. EPA-approved Crypton Disinfectant & Deodorizer.

From fabric, carpet, leather, wall and mattress to pet beds, home accessories, bags and luggage – our mission is to give customers more ways to live healthy, live beautifully and Live Clean®.

While there is no incontrovertible proof that silver nanoparticles and/or silver ions are a serious threat to the environment, it would be nice to see companies acknowledge some of the concerns.

Water wears away stone at Rice University (Texas, US) and at the University of Bremen (Germany)

I am fascinated by research that focuses on boundaries as does this work from Rice University (Texas, US) and the University of Bremen (Germany) but first a general description of the research from a Dec. 6, 2013 news item on Nanowerk (Note: A link has been removed),

Scientists from Rice University and the University of Bremen’s Center for Marine Environmental Sciences (MARUM) in Germany have combined cutting-edge experimental techniques and computer simulations to find a new way of predicting how water dissolves crystalline structures like those found in natural stone and cement.

In a new study featured on the cover of the Nov. 28 issue of the Journal of Physical Chemistry C (“Kinetic Monte Carlo Simulations of Silicate Dissolution: Model Complexity and Parametrization”), the team found their method was more efficient at predicting the dissolution rates of crystalline structures in water than previous methods. The research could have wide-ranging impacts in diverse areas, including water quality and planning, environmental sustainability, corrosion resistance and cement construction.

The Dec. 5, 2013 Rice University news release, which originated the news item, explains the reasons for the research and delves into the subject of boundaries,

“We need to gain a better understanding of dissolution mechanisms to better predict the fate of certain materials, both in nature and in man-made systems,” said lead investigator Andreas Lüttge, a professor of mineralogy at MARUM and professor emeritus and research professor in Earth science at Rice. His team specializes in studying the thin boundary layer that forms between minerals and fluids.

Boundary layers are ubiquitous in nature; they occur when raindrops fall on stone, water seeps through soil and the ocean meets the sea floor. Scientists and engineers have long been interested in accurately explaining how crystalline materials, including many minerals and stones, interact with and are dissolved by water. Calculations about the rate of these dissolution processes are critical in many fields of science and engineering.

In the new study, Lüttge and lead author Inna Kurganskaya, a research associate in Earth science at Rice, studied dissolution processes using quartz, one of the most common minerals found in nature. Quartz, or silicon dioxide, is a type of silicate, the most abundant group of minerals in Earth’s crust.

At the boundary layer where quartz and water meet, multiple chemical reactions occur. Some of these happen simultaneously and others take place in succession. In the new study, the researchers sought to create a computerized model that could accurately simulate the complex chemistry at the boundary layer.

“The new model simulates the dissolution kinetics at the boundary layer with greater precision than earlier stochastic models operating at the same scale,” Kurganskaya said. “Existing simulations rely on rate constants assigned to a wide range of possible reactions, and as a result, the total material flux from the surface have an inherent variance range — a plus or minus factor that is always there.”

The team used new equipment to achieve increased imaging precision (from the news release),

One reason the team’s simulations more accurately represent real processes is that its models incorporate actual measurements from cutting-edge instruments and from high-tech materials, including glass ceramics and nanomaterials. With a special imaging technique called “vertical scanning interferometry,” which the group at MARUM and Rice helped to develop, the team scanned the crystal surfaces of both minerals and manufactured materials to generate topographic maps with a resolution of a just a few nanometers, or billionths of a meter.

“We found that dissolution rates that were predicted using rate constants were sometimes off by as much as two orders of magnitude,” Lüttge said.

The new method for more precisely predicting dissolution processes could revolutionize the way engineers and scientists make many calculations related to a myriad of things, including the stability of building materials, the longevity of materials used for radioactive waste storage and more, he said.

“Further work is needed to prove the broad utility of the method,” he said. “In the next phase of research, we plan to test our simulations on larger systems and over longer periods.”

One often sees funding information at the end of these types of news releases, which I don’t usually include here but I found this one a bit surprising (this is the first time I’ve seen research supported by a university that has no researchers involved in the work),

The research was supported by the Global Climate and Energy Project at Stanford University

The researchers offered this image to illustrate their work,

The dissolution process of a crystalline structure in water is shown: two bonded SiO4 -- molecules dissolve (top left), a quartz crystal (top right) and the computer-simulated surface of a dissolving crystalline structure (below). CREDIT: MARUM & Rice University

The dissolution process of a crystalline structure in water is shown: two bonded SiO4 — molecules dissolve (top left), a quartz crystal (top right) and the computer-simulated surface of a dissolving crystalline structure (below). CREDIT: MARUM & Rice University

For those who just can’t get enough information, here’s a link to and a citation for the paper,

Kinetic Monte Carlo Simulations of Silicate Dissolution: Model Complexity and Parametrization by Inna Kurganskaya and Andreas Luttge. J. Phys. Chem. C, 2013, 117 (47), pp 24894–24906 DOI: 10.1021/jp408845m Publication Date (Web): October 10, 2013
Copyright © 2013 American Chemical Society

This paper is behind a paywall.

‘Ship in a bottle’ concept helps to create an artificial nose

I love the description of this latest artificial nose, ,as being based on a ‘ship in a bottle’ concept, from an Oct. 10, 2013 Rice University news release (also on EurekAlert),

Rice University scientists took a lesson from craftsmen of old to assemble microscopic compounds that warn of the presence of dangerous fumes from solvents.

The researchers combined a common mineral, zeolite, with a metallic compound based on rhenium to make an “artificial nose” that can sniff out solvent gases. They found that in the presence of the compound, each gas had a photoluminescent “fingerprint” with a specific intensity, lifetime and color.

The challenge for Martí and his team was to get their large metallic particles through the much smaller pores of a zeolite cage. The answer: Do it old-school. In their process, small chemical components enter the cage, find each other and self-assemble into rhenium complexes. Then they’re stuck — like a ship in a bottle.

The news release goes on to relate how the researchers created their ‘ship in a bottle’ or zeolite cage,

“We sequentially load the individual parts of the complex into the zeolite,” Martí said. “The parts are smaller than the pores, but when they self-assemble inside the zeolite, they’re trapped.” Once washed to eliminate complexes that form outside the zeolites, the compound is ready for use.

The relatively simple technique, which was initially developed and studied by two Rice alumni while they were undergraduate students in Martí’s lab, could provide a scalable, inexpensive platform to monitor toxic vapors from industrial solvents.

Solvents are liquid chemicals, often petroleum-based, that are widely used to dissolve solid materials. They are found in paints, thinners, aerosol sprays, dyes, marking pens, adhesives and many other products.

They also evaporate quickly. Solvent vapors, which are hazardous to inhale and can be highly flammable, are often denser than air and gather at floor level, where they can build to dangerous amounts unless detected.

Martí said platinum, gold, palladium and copper salts are often used to detect vapors, because they change color in the presence of solvents. The rhenium-based supramolecular complex was known to fluoresce in the presence of some solvents, but dealing with vapors is a different story.

“If the complexes are in a solid state, they are too close to each other and gases can’t interact with them,” he said. “So we started thinking of ways to create space between them.”

Enter zeolites. “These zeolites are cages with big cavities and small pores,” Martí said. “The pores are big enough — at about 7.4 angstroms — for most gas-phase molecules to enter. The question was how to trap the bigger rhenium complexes inside.”

Other groups have trapped ruthenium complexes in zeolites, but these complexes were not ideal to detect solvents. Then-undergraduates Ty Hanna and, later, Zack Panos developed the method to put rhenium complexes inside zeolites. The results were outstanding, Martí said.

Like canaries in a coalmine, the caged complexes strongly signal the presence of a vapor by the color and intensity of their photoluminescent glow in ultraviolet light.

Martí said nobody had studied the third key property — the amount of time the complex remains in an excited state. That ranges from less than 1,000 nanoseconds for water and ammonia to “a quite long” 4,000-plus nanoseconds for pyridine. It’s different for every type of vapor, he said.

“We concluded that every individual vapor has a set of photophysical properties that is unique for that solvent,” he said. “Each one has a unique fingerprint.”

With the ability to detect three distinct characteristics for each vapor, a team led by graduate student Avishek Saha built a three-dimensional plot to map the fingerprints of 17 types of solvents. They found categories of solvents — nonpolar, alcohols, protics (which include water) and aprotics — tended to gather in their own areas.

“That’s another interesting thing,” Martí said. “Different solvent groups occupy different areas in the map. So even if a solvent hasn’t been studied, our material will help people recognize the category it falls into.”

He said the group plans to test more solvents and suggested the material may also be useful for detecting the presence of other volatile species like explosives.

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

Three-Dimensional Solvent-Vapor Map Generated by Supramolecular Metal-Complex Entrapment by Avishek Saha, Zack Panos, Ty Hanna, Kewei Huang, Mayra Hernández-Rivera, and Prof. Angel A. Martí.
Angewandte Chemie International Edition Article first published online: 2 OCT 2013 DOI: 10.1002/anie.201305762

Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

The article is behind a paywall.

The reference to a ‘ship in a bottle’ brought me back to my childhood. Our parents had a ‘ship in a bottle’ but neither my sister nor I were allowed to touch it. In fact, it was brought out for viewing purposes only on special occasions. I no longer remember what made it so precious but I do recall how magical it seemed. Luckily the internet has made satisfying one’s curiosity easy; I found a picture and instructions on how to make ‘a ship in a bottle’,

Credit: Goaly (?) [downloaded from http://www.instructables.com/id/Building-A-Ship-In-A-Bottle/]

Credit: Goaly (?) [downloaded from http://www.instructables.com/id/Building-A-Ship-In-A-Bottle/]

You can find instructions by Goaly for Building a Ship in a Bottle here.

Happy Thanksgiving Weekend!

Carbyne vs. graphene

Rice University (Texas, US) researchers are announcing a new carbon-based nanomaterial, carbyne, according an Oct. 9, 2013 news release,

Carbyne will be the strongest of a new class of microscopic materials if and when anyone can make it in bulk.

If they do, they’ll find carbyne nanorods or nanoropes have a host of remarkable and useful properties, as described in a new paper by Rice University theoretical physicist Boris Yakobson and his group. The paper appears this week in the American Chemical Society journal ACS Nano.

Carbyne is a chain of carbon atoms held together by either double or alternating single and triple atomic bonds. That makes it a true one-dimensional material, unlike atom-thin sheets of graphene that have a top and a bottom or hollow nanotubes that have an inside and outside.

According to the portrait drawn from calculations by Yakobson and his group:

* Carbyne’s tensile strength – the ability to withstand stretching – surpasses “that of any other known material” and is double that of graphene. (Scientists had already calculated it would take an elephant on a pencil to break through a sheet of graphene.)

* It has twice the tensile stiffness of graphene and carbon nanotubes and nearly three times that of diamond.

* Stretching carbyne as little as 10 percent alters its electronic band gap significantly.

* If outfitted with molecular handles at the ends, it can also be twisted to alter its band gap. With a 90-degree end-to-end rotation, it becomes a magnetic semiconductor.

Carbyne chains can take on side molecules that may make the chains suitable for energy storage.

* The material is stable at room temperature, largely resisting crosslinks with nearby chains.

That’s a remarkable set of qualities for a simple string of carbon atoms, Yakobson said.

“You could look at it as an ultimately thin graphene ribbon, reduced to just one atom, or an ultimately thin nanotube,” he said. It could be useful for nanomechanical systems, in spintronic devices, as sensors, as strong and light materials for mechanical applications or for energy storage.

“Regardless of the applications,” he said, “academically, it’s very exciting to know the strongest possible assembly of atoms.”

Based on the calculations, he said carbyne might be the highest energy state for stable carbon. “People usually look for what is called the ‘ground state,’ the lowest possible energy configuration for atoms,” Yakobson said. “For carbon, that would be graphite, followed by diamond, then nanotubes, then fullerenes. But nobody asks about the highest energy configuration. We think this may be it, a stable structure at the highest energy possible.”

Theories about carbyne first appeared in the 19th century, and an approximation of the material was first synthesized in the USSR in 1960. Carbyne has since been seen in compressed graphite, has been detected in interstellar dust and has been created in small quantities by experimentalists.

“I have always been interested in the stability of ultimately thin wires of anything and how thin a rod you could make from a given chemical,” Yakobson said. “We had a paper 10 years ago about silicon in which we explored what happens to silicon nanowire as it gets thinner. To me, this was just a part of the same question.”

The Rice researchers, led by Rice graduate student Mingjie Liu and postdoctoral researcher Vasilii Artyukhov, were aware of a number of papers that described one property or another of carbyne. They set out to detail carbyne with computer models using first-principle rules to determine the energetic interactions of atoms, Artyukhov said.

“Our intention was to put it all together, to construct a complete mechanical picture of carbyne as a material,” Artyukhov said. “The fact that it has been observed tells us it’s stable under tension, at least, because otherwise it would just fall apart.”

Yakobson said the researchers were surprised to find that the band gap in carbyne was so sensitive to twisting. “It will be useful as a sensor for torsion or magnetic fields, if you can find a way to attach it to something that will make it twist,” he said. “We didn’t look for this, specifically; it came up as a side product.”

“That’s the good thing about studying things carefully,” Artyukhov said.

Another finding of great interest was the energy barrier that keeps atoms on adjacent carbyne chains from collapsing into each other. “When you’re talking about theoretical material, you always need to be careful to see if it will react with itself,” Artyukhov said. “This has never really been investigated for carbyne.”

The literature seemed to indicate carbyne “was not stable and would form graphite or soot,” he said.

Instead, the researchers found carbon atoms on separate strings might overcome the barrier in one spot, but the rods’ stiffness would prevent them from coming together in a second location, at least at room temperature. “They would look like butterfly wings,” Artyukhov said.

“Bundles might stick to each other, but they wouldn’t collapse completely,” Yakobson added. “That could make for a highly porous, random net that may be good for adsorption.” Artyukhov said the nominal specific area of carbyne is about five times that of graphene.

When the team’s paper became available this summer on arXiv, the scientific press and even some of the popular press were so excited over the calculations that they picked up on the paper and its implications before the team submitted it for peer review. Now that the complete paper is ready for public consumption, the researchers said they’ll carry their investigation in new directions.

They’re taking a more rigorous look at the conductivity of carbyne and are thinking about other elements as well. “We’ve talked about going through different elements in the periodic table to see if some of them can form one-dimensional chains,” Yakobson said.

Given Rice’s prominence in the nanotechnology field and its status as the ‘home’ of the fullerene, aka, buckyballs, this discovery reaffirms the university’s standing.

Here’s a ‘carbyne’ image the researchers have provided,

Rice University researchers have determined from first-principle calculations that carbyne would be the strongest material yet discovered. The carbon-atom chains would be difficult to make but would be twice as strong as two-dimensional graphene sheets. (Credit: Vasilii Artyukhov/Rice University)

Rice University researchers have determined from first-principle calculations that carbyne would be the strongest material yet discovered. The carbon-atom chains would be difficult to make but would be twice as strong as two-dimensional graphene sheets. (Credit: Vasilii Artyukhov/Rice University)

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

Carbyne From First Principles: Chain of C atoms, a Nanorod or a Nanorope by Mingjie Liu , Vasilii I. Artyukhov , Hoonkyung Lee , Fangbo Xu , and Boris I. Yakobson. ACS Nano, Just Accepted Manuscript DOI: 10.1021/nn404177r Publication Date (Web): October 5, 2013
Copyright © 2013 American Chemical Society

This paper is behind a paywall.

ETA Oct. 9, 2013 at 4:40 pm PDT: I forgot to follow through on my headline which refers to graphene, the current ‘wonder’ nanomaterial, and its possible future dethroning by carbyne. I think it unlikely as part of what makes graphene so attractive are the properties that could allow its use in electronics applications, properties which carbyne does not seem to share.