Tag Archives: Angela R. Hight Walker

A standard for determining what it means to be graphene

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How do you know if your ‘graphene’ light bulb has any graphene in it? How do you know if your orange juice is 100% orange juice? The answer to those questions is that you don’t. So, you must hope there are standards and regulations governing the answers. You must also hope that there are incentives (fines and/or jail time) for obeying those regulations.

In a March 15, 2021 news item on Nanowerk, you’ll find an announcement from the UK’s National Physical Laboratory about an international standard for graphene (Note: A link has been removed),

The National Physical Laboratory (NPL) in the UK in collaboration with international partners, have developed an ISO/IEC [International Standards Organization/International Electrotechnical Commission] standard, ISO/TS 21356-1:2021, for measuring the structural properties of graphene, typically sold as powders or in a liquid dispersion. The ISO/IEC standard allows the supply chain to answer the question ‘what is my material?’ and is based on methods developed with The University of Manchester in the NPL Good Practice Guide 145.

A March ??, 2021 NPL press release, which originated the news item, provides more details,

Over the last few years, graphene, a 2D material with many exciting properties and just one atom thick, has moved from the laboratory into real-world products such as cars and smartphones. However, there is still a barrier affecting the rate of its commercialisation, namely, understanding the true properties of the material. There is not just one type of material, but many, each with different properties that need matching to the many different applications where graphene can provide an improvement.

With hundreds of companies across the globe selling different materials labelled as ‘graphene’, and manufacturing it in different ways, end users who want to improve their products by incorporating few-layer graphene flakes are unable to compare and subsequently select the right material for their product.

Through standardised methods to enable the reliable and repeatable measurement of properties, such as the lateral flake size, flake thickness, level of disorder and specific surface area, industry will be able to compare the many materials available and instil trust in the supply chain.  In conjunction with the international ISO/IEC terminology standard led by NPL, ISO/TS 80004-13:2017, it will be possible for commercially available material to be correctly measured and labelled as graphene, few-layer graphene or graphite.

As the UK’s National Metrology Institute, NPL has been developing and standardising the required metrologically-robust methods for the measurement of graphene and related 2D materials to enable industry to use these materials and realise novel and improved products across many application areas.

The continuation of the NPL-led standardisation work within ISO TC229 (nanotechnologies) will allow the chemical properties of graphene related 2D materials to be determined, as well as the structural properties for different forms of graphene material, such as CVD-grown graphene. This truly international effort to standardise the framework of measurements for graphene is described in more detail in Nature Reviews Physics, including further technical discussion on the new ISO graphene measurement standard.

Dr Andrew J Pollard, Science Area Leader at NPL said: “It is exciting to see this new measurement standard now available for the growing graphene industry worldwide. Based on rigorous metrological research, this standard will allow companies to confidently compare technical datasheets for the first time and is the first step towards verified quality control methods.”

Dr Charles Clifford, Senior Research Scientist at NPL said: “It is fantastic to see this international standard published after several years of development.  To reach international consensus especially across the 37 member countries of ISO TC229 (nanotechnologies) is a testament both to the global interest in graphene and the importance of international cooperation.”

James Baker, CEO of Graphene@Manchester said: “Standardisation is crucial for the commercialisation of graphene in many different applications such as construction, water filtration, energy storage and aerospace. Through this international measurement standard, companies in the UK and beyond will be able to accelerate the uptake of this 21st Century material, now entering many significant markets.”

Here are links to the new standard ISO/TS 21356-1:2021 (Nanotechnologies — Structural characterization of graphene — Part 1: Graphene from powders and dispersions} and the NPL/University of Manchester’s 2017 edition of the Good Practice Guide.

Here’s a second link to the article along with a citation,

The importance of international standards for the graphene community by Charles A. Clifford, Erlon H. Martins Ferreira, Toshiyuki Fujimoto, Jan Herrmann, Angela R. Hight Walker, Denis Koltsov, Christian Punckt, Lingling Ren, Gregory J. Smallwood & Andrew J. Pollard. Nature Reviews Physics (2021) DOI: https://doi.org/10.1038/s42254-021-00278-6 Published 15 March 2021

This paper is behind a paywall.

Textiles laced with carbon nanotubes for clothing that protects against poison gas

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The last time I featured carbon nanotube-infused clothing was in a Nov. 4, 2013 post featuring a $20,000+ bulletproof business suit. It now seems that carbon nanotubes in clothing might also be used to protect the wearer against poison gases (from a May 7, 2014 news item on Nanowerk; Note:  A link has been removed),

Nerve agents are among the world’s most feared chemical weapons, but scientists at the National Institute of Standards and Technology (NIST) have demonstrated a way to engineer carbon nanotubes to dismantle the molecules of a major class of these chemicals (“Functionalized, carbon nanotube material for the catalytic degradation of organophosphate nerve agents”). In principle, they say, the nanotubes could be woven into clothing that destroys the nerve agents on contact before they reach the skin.

A May 6, 2014 US NIST news release, which originated the news item, describes the research in more detail,

The team’s experiments show that [carbon] nanotubes—special molecules that resemble cylinders formed of chicken wire—can be combined with a copper-based catalyst able to break apart a key chemical bond in the class of nerve agents that includes Sarin. A small amount of catalyst can break this bond in a large number of molecules, potentially rendering a nerve agent far less harmful. Because nanotubes further enhance the breakdown capability of the catalyst and can be woven into fabric easily, the NIST team members say the findings could help protect military personnel involved in cleanup operations.

Sarin—used in a 1995 Tokyo subway attack—is one of several deadly nerve agents of a group called organophosphates. Many are classified as weapons of mass destruction. While organophosphates are harmful if inhaled, they also are dangerous if absorbed through the skin, and can be even be re-released from clothing if not thoroughly decontaminated.

To protect themselves during research, the team did not work with actual nerve agents, but instead used a “mimic molecule” that contains a chemical bond identical to the one found in organophosphates. Breaking this bond splits the molecule into pieces that are far less dangerous.

The team developed a way to attach the catalyst molecule to the nanotubes and then tested the effectiveness of the tube-catalyst complex to break the bonds. To perform the test, the complex was deposited onto a small sheet of paper and put into a solution containing the mimic molecule. For comparison, the catalyst without nanotubes was tested simultaneously in a different solution. Then it was a simple matter of stirring and watching chemistry in action.

“The solution was initially transparent, almost like water,” says the team’s John Heddleston, “but as soon as we added the paper, the solution started to turn yellow as the breakdown product accumulated. Measuring this color change over time told us the amount and rate of catalysis. We began to see a noticeable difference within an hour, and the longer we left it, the more yellow it became.” The catalyst-nanotube complex far outperformed the catalyst alone.

Principal investigator Angela Hight Walker says that several questions will need to be addressed before catalytic nanotubes start showing up in clothing, such as whether it is better to add the catalyst to the nanotubes before or after they are woven into the fabric.

“We’d also like to find ways to make the catalytic reaction go faster, which is always better,” Hight Walker says. “But our research group has been focusing on the fundamental science of nanoparticles for years, so we are in a good position to answer these questions.”

It’s not clear to me if this technique of combining carbon nanotubes with copper for protection against poison gas will affect, adversely or otherwise, the bulletproofing properties associated with carbon nanotubes. In any event, here’s a link to and a citation for the paper from the NIST researchers,

Functionalized, carbon nanotube material for the catalytic degradation of organophosphate nerve agents by Mark M. Bailey, John M. Heddleston, Jeffrey Davis, Jessica L. Staymates, & Angela R. Hight Walker.  Nano Research March 2014, Volume 7, Issue 3, pp 390-398

This paper is behind a paywall.

Rice U and the US National Institute of Standards and Technology settle into armchairs, the carbon nanotube kind

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An armchair carbon nanotube is amongst the most desirable of carbon nanotubes. You’ll have to look carefully to see the resemblance to an armchair,

Armchair carbon nanotubes, so named for the arrangement of atoms that make their ends look like armchairs, are the most desirable among nanotube researchers for their superior electrical properties. Image by Erik Hároz [downloaded from http://news.rice.edu/2013/02/05/essential-armchair-reading-for-nanotube-researchers-2/]

Armchair carbon nanotubes, so named for the arrangement of atoms that make their ends look like armchairs, are the most desirable among nanotube researchers for their superior electrical properties. Image by Erik Hároz [downloaded from http://news.rice.edu/2013/02/05/essential-armchair-reading-for-nanotube-researchers-2/]

The Feb. 6, 2013 news item on phys.org about the armchair carbon nanotubes notes that this latest research is an early outcome from a recently announced (Oct. 2012) partnership between Rice University and the US National Institute of Standards and Technology (NIST). Trom the news item (Note: Links have been removed),

The first fruits of a cooperative venture between scientists at Rice University and the National Institute of Standards and Technology (NIST) have appeared in a paper that brings together a wealth of information for those who wish to use the unique properties of metallic carbon nanotubes.

The feature article published recently in the Royal Society of Chemistry journal Nanoscale gathers research about the separation and fundamental characteristics of armchair carbon nanotubes, which have been of particular interest to researchers trying to tune their electronic and optical properties.

The Rice University Feb. 5, 2013 news release by Mike Williams, which originated the news item, describe s the process the scientists undertook,

This paper, said Rice physicist Junichiro Kono, provides scientists a valuable resource for detailed information about metallic carbon nanotubes, especially armchair nanotubes. “Basically, we summarized all our recent findings as well as all information we could find in the literature about metallic nanotubes, along with detailed accounts of preparation methods for metal-enriched nanotube samples, to show the community just how much we now understand about these one-dimensional metals,” he said.

As part of the lengthy work, the team compiled and published tables of essential statistics, including optical properties, for a variety of metallic nanotubes. “We provide fundamental theoretical backgrounds and then show very detailed experimental results on unique properties of metallic nanotubes,” Kono said. “This paper summarizes what kind of aspects are understood, and what is not, about fundamental optical processes in nanotubes and will make it easier for researchers to identify their spectroscopic features and transition energies.”

For this of us who are less well versed on armchair carbon nanotubes and their electronic and optical properties, the news releases provides some information (Note: Links have been removed),

Nanotubes come in many flavors, depending on their chirality. Chirality is a characteristic akin to the angles at which a flat sheet of paper might align when wrapped into a tube. Cut the tube in half and the atoms at the open edge would line up in the shape of an armchair, a zigzag or some variant. Even though their raw material is identical – chicken-wire-like hexagons of carbon – the chirality makes all the difference in how nanotubes transmit electricity.

Armchairs are the most coveted because they have no band gap; electrons flow through without resistance. Cables made with armchair nanotubes have the potential to move electricity over great distances with virtually no loss. That makes them the gold standard as the basic element of armchair quantum wire. The ongoing development of this very strong, lightweight, high-capacity cable could improve further the record properties of multifunctional carbon nanotube fibers that are being developed by the group of Rice Professor Matteo Pasquali.

For the project-specific work the scientists performed (Note: Links have been removed),

The new work led by Kono and Robert Hauge, a distinguished faculty fellow in chemistry at Rice, along with scientists at NIST and Los Alamos National Laboratory, looks beyond the armchair’s established electrical properties to further detail their potential for electronic, sensing, optical and photonic devices.

“Of course, to get there, we need really good samples,” Kono said. “Many applications will rely on our ability to separate carbon nanotubes and then assemble macroscopically ordered structures consisting of single-chirality nanotubes. Nobody can do that at this point.”

When a batch of nanotubes comes out of a furnace, it’s a jumble of types. That makes detailed analysis of their characteristics — let alone their practical use — a challenge.

But techniques developed in recent years at Rice and by NIST scientist Ming Zheng to purify metallic nanotubes are beginning to change that. Rice graduate student Erik Hároz said recent experiments established “unambiguous evidence” that a process he and Kono are using called density gradient ultracentrifugation can enrich ensemble samples of armchairs. Taking things further, Zheng’s method of DNA-based ion-exchange chromatography provides very small samples of ultrapure armchair nanotubes of a single chirality.

You can read more about the work at phys.org or at Rice University using the links already provided. For those who’d like to read the research,

Fundamental optical processes in armchair carbon nanotubes by Erik H. Hároz ,  Juan G. Duque,  Xiaomin Tu ,  Ming Zheng ,  Angela R. Hight Walker ,  Robert H. Hauge ,  Stephen K. Doorn and Junichiro Kono. Nanoscale, 2013,5, 1411-1439 DOI: 10.1039/C2NR32769D First published on the web 04 Jan 2013

This article is behind a paywall of sorts.  RSC (Royal Society of Chemistry) Publishing (which publishes Nanoscale) has an open access policy but there are various options, from the RSC Publishing’s Open Access Policy webpage,

RSC Open Access statement

Open Access is the term given to making electronic versions of articles accessible to readers, without any subscription or ‘access side’ fees.

RSC supports Open Access models which seek to ensure that scholarly publishing activities operate in a long term sustainable way.

  • Our fundamental goal is to advance the chemical sciences, through the effective dissemination of high quality research content
  • We seek to maximise the dissemination of the research that we publish
  • We support any and all sustainable and fair models of access. We believe that the integrity and archiving of scholarly content must be maintained throughout
  • We support ‘Gold’* Open Access and encourage funding to be made available to support authors during any transition from reader to author side payments
  • We support the author’s ability to choose where they publish their work to the benefit of the advancement of science. We do not wish authors to be discriminated against if they are unable to pay author-side fees
  • We seek to work closely with other parties, including funders and government agencies, to achieve the above goals

RSC Publishing provides authors with the option to make their article Open Access, through payment of a fee on acceptance. Authors following the traditional route still have deposition options – details are on the ‘Deposition and Licence to Publish’ page of the website.

*There are several types of Open Access:

  • Gold Open Access: Publication costs are covered by an ‘Article Processing Fees’ being paid by authors upon acceptance. The final ‘article of record’ is made available to all, immediately, without any barriers to access
  • Green Open Access: A version of the paper (often the author’s manuscript) is made available via a subject or institutional repository. An embargo period is often involved, typically 6-24 months. No payment is made, and publishers should strive to recoup their investment through traditional sales during the embargo period
  • Delayed Open Access: The final version of the paper is made available by the publisher after an embargo period (e.g. publisher deposit the paper in PubMed after 12 months)

It would seem the option for this article is ‘Delayed Open Access’.