Tag Archives: James M. Tour

Turning asphaltene into graphene

Asphaltene (or asphaltenes are) is waste material that can be turned into graphene according to scientists at Rice University (Texas, US), from a November 18, 2022 news item on ScienceDaily,

Asphaltenes, a byproduct of crude oil production, are a waste material with potential. Rice University scientists are determined to find it by converting the carbon-rich resource into useful graphene.

Muhammad Rahman, an assistant research professor of materials science and nanoengineering, is employing Rice’s unique flash Joule heating process to convert asphaltenes instantly into turbostratic (loosely aligned) graphene and mix it into composites for thermal, anti-corrosion and 3D-printing applications.

The process makes good use of material otherwise burned for reuse as fuel or discarded into tailing ponds and landfills. Using at least some of the world’s reserve of more than 1 trillion barrels of asphaltene as a feedstock for graphene would be good for the environment as well.

A November 17, 2022 Rice University news release (also on EurekAlert), which originated the news item, expands on this exciting news, Note: Links have been removed,

“Asphaltene is a big headache for the oil industry, and I think there will be a lot of interest in this,” said Rahman, who characterized the process as both a scalable and sustainable way to reduce carbon emissions from burning asphaltene.

Rahman is a lead corresponding author of the paper in Science Advances co-led by Rice chemist James Tour, whose lab developed flash Joule heating, materials scientist Pulickel Ajayan and Md Golam Kibria, an assistant professor of chemical and petroleum engineering at the University of Calgary, Canada.

Asphaltenes are 70% to 80% carbon already. The Rice lab combines it with about 20% of carbon black to add conductivity and flashes it with a jolt of electricity, turning it into graphene in less than a second. Other elements in the feedstock, including hydrogen, nitrogen, oxygen and sulfur, are vented away as gases.

“We try to keep the carbon black content as low as possible because we want to maximize the utilization of asphaltene,” Rahman said.

“The government has been putting pressure on the petroleum industries to take care of this,” said Rice graduate student and co-lead author M.A.S.R. Saadi. “There are billions of barrels of asphaltene available, so we began working on this project primarily to see if we could make carbon fiber. That led us to think maybe we should try making graphene with flash Joule heating.”

Assured that Tour’s process worked as well on asphaltene as it did on various other feedstocks, including plastic, electronic waste, tires, coal fly ash and even car parts, the researchers set about making things with their graphene. 

Saadi, who works with Rahman and Ajayan, mixed the graphene into composites, and then into polymer inks bound for 3D printers. “We’ve optimized the ink rheology to show that it is printable,” he said, noting the inks have no more than 10% of graphene mixed in. Mechanical testing of printed objects is forthcoming, he said.

Rice graduate student Paul Advincula, a member of the Tour lab, is co-lead author of the paper. Co-authors are Rice graduate students Md Shajedul Hoque Thakur, Ali Khater, Jacob Beckham and Minghe Lou, undergraduate Aasha Zinke and postdoctoral researcher Soumyabrata Roy; research fellow Shabab Saad, alumnus Ali Shayesteh Zeraati, graduate student Shariful Kibria Nabil and postdoctoral associate Md Abdullah Al Bari of the University of Calgary; graduate student Sravani Bheemasetti and Venkataramana Gadhamshetty, an associate professor, at the South Dakota School of Mines and Technology and its 2D Materials of Biofilm Engineering Science and Technology Center; and research assistant Yiwen Zheng and Aniruddh Vashisth, an assistant professor of mechanical engineering, of the University of Washington.

The research was funded by the Alberta Innovates for Carbon Fiber Grand Challenge programs, the Air Force Office of Scientific Research (FA9550-19-1-0296), the U.S. Army Corps of Engineers (W912HZ-21-2-0050) and the National Science Foundation (1849206, 1920954).  

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

Sustainable valorization of asphaltenes via flash joule heating by M.A.S.R. Saadi, Paul A. Advincula, Md Shajedul Hoque Thakur, Ali Zein Khater, Shabab Saad, Ali Shayesteh Zeraati, Shariful Kibria Nabil, Aasha Zinke, Soumyabrata Roy, Minghe Lou, Sravani N. Bheemasetti, Md Abdullah Al Bari, Yiwen Zheng, Jacob L. Beckham, Venkataramana Gadhamshetty, Aniruddh Vashisth, Md Golam Kibria, James M. Tour, Pulickel M. Ajayan, and Muhammad M. Rahman. Science Advances 18 Nov 2022 Vol 8, Issue 46 DOI: 10.1126/sciadv.add3555

This paper is open access.

Where do I stand? a graphene artwork

A May 2,2019 news item on Nanowerk describes some graphene-based artwork being created at Rice University (Texas, US), Note: A link has been removed,

When you read about electrifying art, “electrifying” isn’t usually a verb. But an artist working with a Rice University lab is in fact making artwork that can deliver a jolt.

The Rice lab of chemist James Tour introduced laser-induced graphene (LIG) to the world in 2014, and now the researchers are making art with the technique, which involves converting carbon in a common polymer or other material into microscopic flakes of graphene.

The “ink” in “Where Do I Stand?” by artist Joseph Cohen is actually laser-induced graphene (LIG). The design shows Cohen’s impression of what LIG looks like at the microscopic level. The work was produced in the Rice University lab where the technique of creating LIG was invented. Photo by Jeff Fitlow
A detail from “Where Do I Stand?” by artist Joseph Cohen, who created the work at Rice University using laser-induced graphene as the medium. Photo by Jeff Fitlow

A May 2, 2019 Rice university news release (also received via email), which originated the news item, describes laser-induced graphene (LIG) and the art in more detail (Note: Links have been removed),

LIG is metallic and conducts electricity. The interconnected flakes are effectively a wire that could empower electronic artworks.

The paper in the American Chemical Society journal ACS Applied Nano Materials – simply titled “Graphene Art” – lays out how the lab and Houston artist and co-author Joseph Cohen generated LIG portraits and prints, including a graphene-inspired landscape called “Where Do I Stand?”

While the work isn’t electrified, Cohen said it lays the groundwork for future possibilities.

“That’s what I would like to do,” he said. “Not make it kitsch or play off the novelty, but to have it have some true functionality that allows greater awareness about the material and opens up the experience.”

Cohen created the design in an illustration program and sent it directly to the industrial engraving laser Tour’s lab uses to create LIG on a variety of materials. The laser burned the artist’s fine lines into the substrate, in this case archive-quality paper treated with fire retardant.

The piece, which was part of Cohen’s exhibit at Rice’s BioScience Research Collaborative last year, peers into the depths of what a viewer shrunken to nanoscale might see when facing a field of LIG, with overlapping hexagons – the basic lattice of atom-thick graphene – disappearing into the distance.

“You’re looking at this image of a 3D foam matrix of laser-induced graphene and it’s actually made of LIG,” he said. “I didn’t base it on anything; I was just thinking about what it would look like. When I shared it with Jim, he said, ‘Wow, that’s what it would look like if you could really blow this up.’”

Cohen said his art is about media specificity.

“In terms of the artistic application, you’re not looking at a representation of something, as traditionally we would in the history of art,” he said. “Each piece is 100% original. That’s the key.”

He developed an interest in nanomaterials as media for his art when he began work with Rice alumnus Daniel Heller, a bioengineer at Memorial Sloan Kettering Cancer Center in New York who established an artist-in-residency position in his lab.

After two years of creating with carbon nanotube-infused paint, Cohen attended an Electrochemical Society conference and met Tour, who in turn introduced him to Rice chemists Bruce Weisman and Paul Cherukuri, who further inspired his investigation of nanotechnology.

The rest is art history.

It would be incorrect to think of the process as “printing,” Tour said. Instead of adding a substance to the treated paper, substance is burned away as the laser turns the surface into foamlike flakes of interconnected graphene.

The art itself can be much more than eye candy, given LIG’s potential for electronic applications like sensors or as triboelectric generators that turn mechanical actions into current.

“You could put LIG on your back and have it flash LEDs with every step you take,” Tour said.

The fact that graphene is a conductor — unlike paint, ink or graphite from a pencil — makes it particularly appealing to Cohen, who expects to take advantage of that capability in future works.

“It’s art with a capital A that is trying to do the most that it can with advancements in science and technology,” he said. “If we look back historically, from the Renaissance to today, the highest forms of art push the limits of human understanding.”

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

Graphene Art by Yieu Chyan, Joseph Cohen, Winston Wang, Chenhao Zhang, and James M. Tour. ACS Appl. Nano Mater., Article ASAP DOI: 10.1021/acsanm.9b00391 Publication Date (Web): April 23, 2019

Copyright © 2019 American Chemical Society

This paper appears to be open access.

Because I can’t resist the delight beaming from these faces,

maging with laser-induced graphene (LIG) was taken to a new level in a Rice University lab. From left, chemist James Tour, holding a portrait of himself in LIG; artist Joseph Cohen, holding his work “Where Do I Stand?”; and Yieu Chyan, a Rice graduate student and lead author of a new paper detailing the process used to create the art. Photo by Jeff Fitlow

Do you want that coffee with some graphene on toast?

These scientists are excited:

For those who prefer text, here’s the Rice University Feb. 13, 2018 news release (received via email and available online here and on EurekAlert here) Note: Links have been removed),

Rice University scientists who introduced laser-induced graphene (LIG) have enhanced their technique to produce what may become a new class of edible electronics.

The Rice lab of chemist James Tour, which once turned Girl Scout cookies into graphene, is investigating ways to write graphene patterns onto food and other materials to quickly embed conductive identification tags and sensors into the products themselves.

“This is not ink,” Tour said. “This is taking the material itself and converting it into graphene.”

The process is an extension of the Tour lab’s contention that anything with the proper carbon content can be turned into graphene. In recent years, the lab has developed and expanded upon its method to make graphene foam by using a commercial laser to transform the top layer of an inexpensive polymer film.

The foam consists of microscopic, cross-linked flakes of graphene, the two-dimensional form of carbon. LIG can be written into target materials in patterns and used as a supercapacitor, an electrocatalyst for fuel cells, radio-frequency identification (RFID) antennas and biological sensors, among other potential applications.

The new work reported in the American Chemical Society journal ACS Nano demonstrated that laser-induced graphene can be burned into paper, cardboard, cloth, coal and certain foods, even toast.

“Very often, we don’t see the advantage of something until we make it available,” Tour said. “Perhaps all food will have a tiny RFID tag that gives you information about where it’s been, how long it’s been stored, its country and city of origin and the path it took to get to your table.”

He said LIG tags could also be sensors that detect E. coli or other microorganisms on food. “They could light up and give you a signal that you don’t want to eat this,” Tour said. “All that could be placed not on a separate tag on the food, but on the food itself.”

Multiple laser passes with a defocused beam allowed the researchers to write LIG patterns into cloth, paper, potatoes, coconut shells and cork, as well as toast. (The bread is toasted first to “carbonize” the surface.) The process happens in air at ambient temperatures.

“In some cases, multiple lasing creates a two-step reaction,” Tour said. “First, the laser photothermally converts the target surface into amorphous carbon. Then on subsequent passes of the laser, the selective absorption of infrared light turns the amorphous carbon into LIG. We discovered that the wavelength clearly matters.”

The researchers turned to multiple lasing and defocusing when they discovered that simply turning up the laser’s power didn’t make better graphene on a coconut or other organic materials. But adjusting the process allowed them to make a micro supercapacitor in the shape of a Rice “R” on their twice-lased coconut skin.

Defocusing the laser sped the process for many materials as the wider beam allowed each spot on a target to be lased many times in a single raster scan. That also allowed for fine control over the product, Tour said. Defocusing allowed them to turn previously unsuitable polyetherimide into LIG.

“We also found we could take bread or paper or cloth and add fire retardant to them to promote the formation of amorphous carbon,” said Rice graduate student Yieu Chyan, co-lead author of the paper. “Now we’re able to take all these materials and convert them directly in air without requiring a controlled atmosphere box or more complicated methods.”

The common element of all the targeted materials appears to be lignin, Tour said. An earlier study relied on lignin, a complex organic polymer that forms rigid cell walls, as a carbon precursor to burn LIG in oven-dried wood. Cork, coconut shells and potato skins have even higher lignin content, which made it easier to convert them to graphene.

Tour said flexible, wearable electronics may be an early market for the technique. “This has applications to put conductive traces on clothing, whether you want to heat the clothing or add a sensor or conductive pattern,” he said.

Rice alumnus Ruquan Ye is co-lead author of the study. Co-authors are Rice graduate student Yilun Li and postdoctoral fellow Swatantra Pratap Singh and Professor Christopher Arnusch of Ben-Gurion University of the Negev, Israel. Tour is the T.T. and W.F. Chao Chair in Chemistry as well as a professor of computer science and of materials science and nanoengineering at Rice.

The Air Force Office of Scientific Research supported the research.

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

Laser-Induced Graphene by Multiple Lasing: Toward Electronics on Cloth, Paper, and Food by Yieu Chyan, Ruquan Ye†, Yilun Li, Swatantra Pratap Singh, Christopher J. Arnusch, and James M. Tour. ACS Nano DOI: 10.1021/acsnano.7b08539 Publication Date (Web): February 13, 2018

Copyright © 2018 American Chemical Society

This paper is behind a paywall.

h/t Feb. 13, 2018 news item on Nanowerk

Tattoo therapy for chronic disease?

It’s good to wake up to something truly new. In this case, it’s using tattoos and nanoparticles for medical applications. From a Sept. 22, 2016 news item on ScienceDaily,

A temporary tattoo to help control a chronic disease might someday be possible, according to scientists at Baylor College of Medicine [Texas, US] who tested antioxidant nanoparticles created at Rice University [Texas, US].

A Sept. 22, 2016 Rice University news release, which originated the news item, provides more information and some good explanations of the terms used (Note: Links have been removed),

A proof-of-principle study led by Baylor scientist Christine Beeton published today by Nature’s online, open-access journal Scientific Reports shows that nanoparticles modified with polyethylene glycol are conveniently choosy as they are taken up by cells in the immune system.

That could be a plus for patients with autoimmune diseases like multiple sclerosis, one focus of study at the Beeton lab. “Placed just under the skin, the carbon-based particles form a dark spot that fades over about one week as they are slowly released into the circulation,” Beeton said.

T and B lymphocyte cells and macrophages are key components of the immune system. However, in many autoimmune diseases such as multiple sclerosis, T cells are the key players. One suspected cause is that T cells lose their ability to distinguish between invaders and healthy tissue and attack both.

In tests at Baylor, nanoparticles were internalized by T cells, which inhibited their function, but ignored by macrophages. “The ability to selectively inhibit one type of cell over others in the same environment may help doctors gain more control over autoimmune diseases,” Beeton said.

“The majority of current treatments are general, broad-spectrum immunosuppressants,” said Redwan Huq, lead author of the study and a graduate student in the Beeton lab. “They’re going to affect all of these cells, but patients are exposed to side effects (ranging) from infections to increased chances of developing cancer. So we get excited when we see something new that could potentially enable selectivity.” Since the macrophages and other splenic immune cells are unaffected, most of a patient’s existing immune system remains intact, he said.

The soluble nanoparticles synthesized by the Rice lab of chemist James Tour have shown no signs of acute toxicity in prior rodent studies, Huq said. They combine polyethylene glycol with hydrophilic carbon clusters, hence their name, PEG-HCCs. The carbon clusters are 35 nanometers long, 3 nanometers wide and an atom thick, and bulk up to about 100 nanometers in globular form with the addition of PEG. They have proven to be efficient scavengers of reactive oxygen species called superoxide molecules, which are expressed by cells the immune system uses to kill invading microorganisms.

T cells use superoxide in a signaling step to become activated. PEG-HCCs remove this superoxide from the T cells, preventing their activation without killing the cells.

Beeton became aware of PEG-HCCs during a presentation by former Baylor graduate student Taeko Inoue, a co-author of the new study. “As she talked, I was thinking, ‘That has to work in models of multiple sclerosis,’” Beeton said. “I didn’t have a good scientific rationale, but I asked for a small sample of PEG-HCCs to see if they affected immune cells.

“We found they affected the T lymphocytes and not the other splenic immune cells, like the macrophages. It was completely unexpected,” she said.

The Baylor lab’s tests on animal models showed that small amounts of PEG-HCCs injected under the skin are slowly taken up by T lymphocytes, where they collect and inhibit the cell’s function. They also found the nanoparticles did not remain in T cells and dispersed within days after uptake by the cells.

“That’s an issue because you want a drug that’s in the system long enough to be effective, but not so long that, if you have a problem, you can’t remove it,” Beeton said. “PEG-HCCs can be administered for slow release and don’t stay in the system for long. This gives us much better control over the circulating half-life.”

“The more we study the abilities of these nanoparticles, the more surprised we are at how useful they could be for medical applications,” Tour said. The Rice lab has published papers with collaborators at Baylor and elsewhere on using functionalized nanoparticles to deliver cancer drugs to tumors and to quench the overproduction of superoxides after traumatic brain injuries.

Beeton suggested delivering carbon nanoparticles just under the skin rather than into the bloodstream would keep them in the system longer, making them more available for uptake by T cells. And the one drawback – a temporary but visible spot on the skin that looks like a tattoo – could actually be a perk to some.

“We saw it made a black mark when we injected it, and at first we thought that’s going to be a real problem if we ever take it into the clinic,” Beeton said. “But we can work around that. We can inject into an area that’s hidden, or use micropattern needles and shape it.

“I can see doing this for a child who wants a tattoo and could never get her parents to go along,” she said. “This will be a good way to convince them.”

The research was supported by Baylor College of Medicine, the National Multiple Sclerosis Society, National Institutes of Health, the Dan L. Duncan Cancer Center, John S. Dunn Gulf Coast Consortium for Chemical Genomics and the U.S. Army-funded Traumatic Brain Injury Consortium.

That’s an interesting list of funders at the end of the news release.

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

Preferential uptake of antioxidant carbon nanoparticles by T lymphocytes for immunomodulation by Redwan Huq, Errol L. G. Samuel, William K. A. Sikkema, Lizanne G. Nilewski, Thomas Lee, Mark R. Tanner, Fatima S. Khan, Paul C. Porter, Rajeev B. Tajhya, Rutvik S. Patel, Taeko Inoue, Robia G. Pautler, David B. Corry, James M. Tour, & Christine Beeton. Scientific Reports 6, Article number: 33808 (2016) doi:10.1038/srep33808 Published online: 22 September 2016

This paper is open access.

Here’s an image provided by the researchers,

Polyethylene glycol-hydrophilic carbon clusters developed at Rice University were shown to be selectively taken up by T cells, which inhibits their function, in tests at Baylor College of Medicine. The researchers said the nanoparticles could lead to new strategies for controlling autoimmune diseases like multiple sclerosis. (Credit: Errol Samuel/Rice University) - See more at: http://news.rice.edu/2016/09/22/tattoo-therapy-could-ease-chronic-disease/#sthash.sIfs3b0S.dpuf

Polyethylene glycol-hydrophilic carbon clusters developed at Rice University were shown to be selectively taken up by T cells, which inhibits their function, in tests at Baylor College of Medicine. The researchers said the nanoparticles could lead to new strategies for controlling autoimmune diseases like multiple sclerosis. (Credit: Errol Samuel/Rice University)

Carbon capture with asphalt

I wish I could turn back the clock a few years, so I could mention this research from Rice University (Texas, US) on using asphalt for carbon capture (more on why at the end of this post). From a Sept. 13, 2016 news item on Nanowerk (Note: A link has been removed),

Rice University laboratory has improved its method to turn plain asphalt into a porous material that can capture greenhouse gases from natural gas.

In research detailed this month in Advanced Energy Materials (“Ultra-High Surface Area Activated Porous Asphalt for CO2 Capture through Competitive Adsorption at High Pressures”), Rice researchers showed that a new form of the material can sequester 154 percent of its weight in carbon dioxide at high pressures that are common at gas wellheads.

A Sept. 12, 2016 Rice University news release, which originated the news item, further describes the work (Note: Links have been removed),

Raw natural gas typically contains between 2 and 10 percent carbon dioxide and other impurities, which must be removed before the gas can be sold. The cleanup process is complicated and expensive and most often involves flowing the gas through fluids called amines that can soak up and remove about 15 percent of their own weight in carbon dioxide. The amine process also requires a great deal of energy to recycle the fluids for further use.

“It’s a big energy sink,” said Rice chemist James Tour, whose lab developed a technique last year to turn asphalt into a tough, sponge-like substance that could be used in place of amines to remove carbon dioxide from natural gas as it was pumped from ocean wellheads.

Initial field tests in 2015 found that pressure at the wellhead made it possible for that asphalt material to adsorb, or soak up, 114 percent of its weight in carbon at ambient temperatures.

Tour said the new, improved asphalt sorbent is made in two steps from a less expensive form of asphalt, which makes it more practical for industry.

“This shows we can take the least expensive form of asphalt and make it into this very high surface area material to capture carbon dioxide,” Tour said. “Before, we could only use a very expensive form of asphalt that was not readily available.”

The lab heated a common type asphalt known as Gilsonite at ambient pressure to eliminate unneeded organic molecules, and then heated it again in the presence of potassium hydroxide for about 20 minutes to synthesize oxygen-enhanced porous carbon with a surface area of 4,200 square meters per gram, much higher than that of the previous material.

The Rice lab’s initial asphalt-based porous carbon collected carbon dioxide from gas streams under pressure at the wellhead and released it when the pressure was released. The carbon dioxide could then be repurposed or pumped back underground while the porous carbon could be reused immediately.

In the latest tests with its new material, Tours group showed its new sorbent could remove carbon dioxide at 54 bar pressure. One bar is roughly equal to atmospheric pressure at sea level, and the 54 bar measure in the latest experiments is characteristic of the pressure levels typically found at natural gas wellheads, Tour said.

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

Ultra-High Surface Area Activated Porous Asphalt for CO2 Capture through Competitive Adsorption at High Pressures by Almaz S. Jalilov, Yilun Li, Jian Tian, James M. Tour.  Advanced Energy Materials DOI: 10.1002/aenm.201600693  First published [online]: 8 September 2016

This paper is behind a paywall.

Finishing the story I started at the beginning of this post, I was at an early morning political breakfast a few years back when someone seated at our table asked me if there were any nanotechnology applications for carbon sequestration/capture. At the time, I could not bring any such applications to mind. (Sigh) Now I have an answer.

Graphene ribbons in solution bending and twisting like DNA

An Aug. 15, 2016 news item on ScienceDaily announces research into graphene nanoribbons and their DNA (deoxyribonucleic acid)-like properties,

Graphene nanoribbons (GNRs) bend and twist easily in solution, making them adaptable for biological uses like DNA analysis, drug delivery and biomimetic applications, according to scientists at Rice University.

Knowing the details of how GNRs behave in a solution will help make them suitable for wide use in biomimetics, according to Rice physicist Ching-Hwa Kiang, whose lab employed its unique capabilities to probe nanoscale materials like cells and proteins in wet environments. Biomimetic materials are those that imitate the forms and properties of natural materials.

An Aug. 15, 2016 Rice University (Texas, US) news release (also on EurekAlert), which originated the news item, describes the ribbons and the research in more detail,

Graphene nanoribbons can be thousands of times longer than they are wide. They can be produced in bulk by chemically “unzipping” carbon nanotubes, a process invented by Rice chemist and co-author James Tour and his lab.

Their size means they can operate on the scale of biological components like proteins and DNA, Kiang said. “We study the mechanical properties of all different kinds of materials, from proteins to cells, but a little different from the way other people do,” she said. “We like to see how materials behave in solution, because that’s where biological things are.” Kiang is a pioneer in developing methods to probe the energy states of proteins as they fold and unfold.

She said Tour suggested her lab have a look at the mechanical properties of GNRs. “It’s a little extra work to study these things in solution rather than dry, but that’s our specialty,” she said.

Nanoribbons are known for adding strength but not weight to solid-state composites, like bicycle frames and tennis rackets, and forming an electrically active matrix. A recent Rice project infused them into an efficient de-icer coating for aircraft.

But in a squishier environment, their ability to conform to surfaces, carry current and strengthen composites could also be valuable.

“It turns out that graphene behaves reasonably well, somewhat similar to other biological materials. But the interesting part is that it behaves differently in a solution than it does in air,” she said. The researchers found that like DNA and proteins, nanoribbons in solution naturally form folds and loops, but can also form helicoids, wrinkles and spirals.

Kiang, Wijeratne [Sithara Wijeratne, Rice graduate now a postdoctoral researcher at Harvard University] and Jingqiang Li, a co-author and student in the Kiang lab, used atomic force microscopy to test their properties. Atomic force microscopy can not only gather high-resolution images but also take sensitive force measurements of nanomaterials by pulling on them. The researchers probed GNRs and their precursors, graphene oxide nanoribbons.

The researchers discovered that all nanoribbons become rigid under stress, but their rigidity increases as oxide molecules are removed to turn graphene oxide nanoribbons into GNRs. They suggested this ability to tune their rigidity should help with the design and fabrication of GNR-biomimetic interfaces.

“Graphene and graphene oxide materials can be functionalized (or modified) to integrate with various biological systems, such as DNA, protein and even cells,” Kiang said. “These have been realized in biological devices, biomolecule detection and molecular medicine. The sensitivity of graphene bio-devices can be improved by using narrow graphene materials like nanoribbons.”

Wijeratne noted graphene nanoribbons are already being tested for use in DNA sequencing, in which strands of DNA are pulled through a nanopore in an electrified material. The base components of DNA affect the electric field, which can be read to identify the bases.

The researchers saw nanoribbons’ biocompatibility as potentially useful for sensors that could travel through the body and report on what they find, not unlike the Tour lab’s nanoreporters that retrieve information from oil wells.

Further studies will focus on the effect of the nanoribbons’ width, which range from 10 to 100 nanometers, on their properties.

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

Detecting the Biopolymer Behavior of Graphene Nanoribbons in Aqueous Solution by Sithara S. Wijeratne, Evgeni S. Penev, Wei Lu, Jingqiang Li, Amanda L. Duque, Boris I. Yakobson, James M. Tour, & Ching-Hwa Kiang. Scientific Reports 6, Article number: 31174 (2016)  doi:10.1038/srep31174 Published online: 09 August 2016

This paper is open access.

A de-icer and a preventative for airplane wings from Rice University

I last mentioned this graphene-based work (from James Tour at Rice University in Texas, US) on de-icing not just airplane wings but also windshields, skyscrapers and more in a Sept. 17, 2014 posting. The latest study indicates the technology could be used as a preventative according to a May 23, 2016 news item on phys.org,

Rice University scientists have advanced their graphene-based de-icer to serve a dual purpose. The new material still melts ice from wings and wires when conditions get too cold. But if the air is above 7 degrees Fahrenheit, ice won’t form at all.

A May 23, 2016 Rice University news release (also on EurekAlert), which originated the news item, goes on to describe the work in more detail,

The Rice lab of chemist James Tour gave its de-icer superhydrophobic (water-repelling) capabilities that passively prevent water from freezing above 7 degrees. The tough film that forms when the de-icer is sprayed on a surface is made of atom-thin graphene nanoribbons that are conductive, so the material can also be heated with electricity to melt ice and snow in colder conditions.

The material can be spray-coated, making it suitable for large applications like aircraft, power lines, radar domes and ships, according to the researchers. …

“We’ve learned to make an ice-resistant material for milder conditions in which heating isn’t even necessary, but having the option is useful,” Tour said. “What we now have is a very thin, robust coating that can keep large areas free of ice and snow in a wide range of conditions.”

Tour, lead authors Tuo Wang, a Rice graduate student, and Yonghao Zheng, a Rice postdoctoral researcher, and their colleagues tested the film on glass and plastic.

Materials are superhydrophobic if they have a water-contact angle larger than 150 degrees. The term refers to the angle at which the surface of the water meets the surface of the material. The greater the beading, the higher the angle. An angle of 0 degrees is basically a puddle, while a maximum angle of 180 degrees defines a sphere just touching the surface.

The Rice films use graphene nanoribbons modified with a fluorine compound to enhance their hydrophobicity. They found that nanoribbons modified with longer perfluorinated chains resulted in films with a higher contact angle, suggesting that the films are tunable for particular conditions, Tour said.

Warming test surfaces to room temperature and cooling again had no effect on the film’s properties, he said.

The researchers discovered that below 7 degrees, water would condense within the structure’s pores, causing the surface to lose both its superhydrophobic and ice-phobic properties. At that point, applying at least 12 volts of electricity warmed them enough to retain its repellant properties.

Applying 40 volts to the film brought it to room temperature, even if the ambient temperature was 25 degrees below zero. Ice allowed to form at that temperature melted after 90 seconds of resistive heating.

The researchers found that while effective, the de-icing mode did not remove water completely, as some remained trapped in the pores between linked nanoribbon bundles. Adding a lubricant with a low melting point (minus 61 degrees F) to the film made the surface slippery, sped de-icing and saved energy.

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

Passive Anti-icing and Active Deicing Films by Tuo Wang, Yonghao Zheng, Abdul-Rahman O. Raji, Yilun Li, William K.A. Sikkema, and James M. Tour. ACS Appl. Mater. Interfaces, Just Accepted Manuscript DOI: 10.1021/acsami.6b03060 Publication Date (Web): May 18, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

Russians offer nanotechnology report at Paris Climate talks

Sadly I cannot find the report presented by the Russians  at the Paris Climate Talks (also known as World Climate Change Conference 2015 [COP21]) but did find this reference to it in a Dec. 7, 2015 article in the New York Times,

One of the surprises of the Paris climate talks was the sudden interest by Russia in appearing as a player in the efforts to reel in greenhouse gases.

The second part occurred on Monday, when an event was added to the schedule of news briefings: “Russia Proposes a New Approach to Climate Change.”

And so Russia did, putting forth a plan — and a report — that in the end seemed largely geared toward promoting a government-funded business, run by a prominent politician.

The Russian Times (rt.com) published a Nov. 30, 2015 article detailing President Vladimir Putin’s address to the conference attendees,

“We have gone beyond the target fixed by the Kyoto Protocol for the period from 1991 to 2012. Russia not only prevented the growth of greenhouse gas emission, by also significantly reduced it,” Putin said.

“Nearly 40 billion tons of carbon dioxide equivalent weren’t released into the atmosphere. As a comparison, the total emissions of all countries in 2012 reached 46 billion tons.”

Russia is planning to keep progressing by bringing breakthrough technologies into practice, “including nanotechnology,” Putin continued saying the country is also open to exchange and share the findings.

Apart from that, Putin has also promised Russia will reduce its polluting emissions by 70 percent by 2030 as compared to base level in 1990.

A Dec. 8, 2015 article by Jasper Nikki De La Cruz for The Science Times provides more detail about the Russian report/proposal (Note: A link has been removed),

Russia proposes a “New Approach” when it comes to dealing with climate change. The proposal focuses on efforts to reduce emissions involving five materials: steel, cement, aluminum, plastic and paper. The proposal is not on the reduction of the production of these materials but rather making these materials lighter, stronger and more efficient. With this approach, nanotechnology is put into the spotlight as the primary technology in making this proposal possible in real-world applications.

Rusnano is a company that is dedicated to nanotechnology. They received $10B of funding from the Russian government. They are pegged to be the frontrunner in research and application of nanotechnology in the production of the mentioned materials.

“Carbon nanotubes have been shown to toughen aluminum, make plastics conductive, extend the life of lithium-ion batteries,” Anatoly B. Chubais, Rusnano founder, said. “So all that is true. Tangentially, that can then lower CO2 emissions, I suppose.”

James Tour, a scientist at Rice University, commented for the New York Times Dec. 7, 2015 article on this suggestion that greater use of carbon nanotubes could reduce emissions,

A report laying out the materials thesis rested heavily on contentions about the use of carbon nanotubes. For a moment that puzzled James M. Tour, a professor of chemistry and materials science at Rice University and an expert on nanomaterials, who was asked about the proposal.

“Carbon nanotubes have been shown to toughen aluminum, make plastics conductive, extend the life of lithium-ion batteries,” he said in an email. “So all that is true. Tangentially, that can then lower CO2 emissions, I suppose.”

But, he added, “All of the above was well known long before Rusnano came around.”

Reporters, too, were confused. When one asked whether the announcement was “a distraction from real action,” Mr. Chubais said the proposal was a means to the same end.

I don’t find the Russian proposal all that outlandish although the emphasis on carbon nanotubes seems a bit outsized (pun intended). In any event, there’s certainly a role for emerging technologies to play in the attempts to change our lifestyles and ameliorate climate change.

A 244-atom submarine powered by light

James Tour lab researchers at Rice University announce in a Nov. 16, 2015 news item on Nanowerk,

Though they’re not quite ready for boarding a lá “Fantastic Voyage,” nanoscale submarines created at Rice University are proving themselves seaworthy.

Each of the single-molecule, 244-atom submersibles built in the Rice lab of chemist James Tour has a motor powered by ultraviolet light. With each full revolution, the motor’s tail-like propeller moves the sub forward 18 nanometers.
And with the motors running at more than a million RPM, that translates into speed. Though the sub’s top speed amounts to less than 1 inch per second, Tour said that’s a breakneck pace on the molecular scale.

“These are the fastest-moving molecules ever seen in solution,” he said.

Expressed in a different way, the researchers reported this month in the American Chemical Society journal Nano Letters that their light-driven nanosubmersibles show an “enhancement in diffusion” of 26 percent. That means the subs diffuse, or spread out, much faster than they already do due to Brownian motion, the random way particles spread in a solution.

While they can’t be steered yet, the study proves molecular motors are powerful enough to drive the sub-10-nanometer subs through solutions of moving molecules of about the same size.

“This is akin to a person walking across a basketball court with 1,000 people throwing basketballs at him,” Tour said.

A Nov. 16, 2015 Rice University news release (also on EurekAlert), which originated the news item, provides context and details about the research,

Tour’s group has extensive experience with molecular machines. A decade ago, his lab introduced the world to nanocars, single-molecule cars with four wheels, axles and independent suspensions that could be “driven” across a surface.

Tour said many scientists have created microscopic machines with motors over the years, but most have either used or generated toxic chemicals. He said a motor that was conceived in the last decade by a group in the Netherlands proved suitable for Rice’s submersibles, which were produced in a 20-step chemical synthesis.

“These motors are well-known and used for different things,” said lead author and Rice graduate student Victor García-López. “But we were the first ones to propose they can be used to propel nanocars and now submersibles.”

The motors, which operate more like a bacteria’s flagellum than a propeller, complete each revolution in four steps. When excited by light, the double bond that holds the rotor to the body becomes a single bond, allowing it to rotate a quarter step. As the motor seeks to return to a lower energy state, it jumps adjacent atoms for another quarter turn. The process repeats as long as the light is on.

For comparison tests, the lab also made submersibles with no motors, slow motors and motors that paddle back and forth. All versions of the submersibles have pontoons that fluoresce red when excited by a laser, according to the researchers. (Yellow, sadly, was not an option.)

“One of the challenges was arming the motors with the appropriate fluorophores for tracking without altering the fast rotation,” García-López said.

Once built, the team turned to Gufeng Wang at North Carolina State University to measure how well the nanosubs moved.

“We had used scanning tunneling microscopy and fluorescence microscopy to watch our cars drive, but that wouldn’t work for the submersibles,” Tour said. “They would drift out of focus pretty quickly.”

The North Carolina team sandwiched a drop of diluted acetonitrile liquid containing a few nanosubs between two slides and used a custom confocal fluorescence microscope to hit it from opposite sides with both ultraviolet light (for the motor) and a red laser (for the pontoons).

The microscope’s laser defined a column of light in the solution within which tracking occurred, García-López said. “That way, the NC State team could guarantee it was analyzing only one molecule at a time,” he said.

Rice’s researchers hope future nanosubs will be able to carry cargoes for medical and other purposes. “There’s a path forward,” García-López said. “This is the first step, and we’ve proven the concept. Now we need to explore opportunities and potential applications.”

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

Unimolecular Submersible Nanomachines. Synthesis, Actuation, and Monitoring by Víctor García-López, Pinn-Tsong Chiang, Fang Chen, Gedeng Ruan, Angel A. Martí, Anatoly B. Kolomeisky, Gufeng Wang, and James M. Tour. Nano Lett., Article ASAP DOI: 10.1021/acs.nanolett.5b03764 Publication Date (Web): November 5, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

There is an illustration of the 244-atom submersible,

Rice University scientists have created light-driven, single-molecule submersibles that contain just 244 atoms. Illustration by Loïc Samuel

Rice University scientists have created light-driven, single-molecule submersibles that contain just 244 atoms. Illustration by Loïc Samuel