Category Archives: manufacturing

New water treatment with 3D-printed graphene aerogels

Caption: Graphene aerogel on a single tissue. Credit: University at Buffalo

That image of the graphene aerogel on a tissue shows off its weightlessness very well.

Here’s more about the graphene aerogel water treatment from an April 14, 2021 news item on Nanowerk,

Graphene excels at removing contaminants from water, but it’s not yet a commercially viable use of the wonder material.

That could be changing.

In a recent study, University at Buffalo [UB] engineers report a new process of 3D printing graphene aerogels that they say overcomes two key hurdles — scalability and creating a version of the material that’s stable enough for repeated use — for water treatment.

“The goal is to safely remove contaminants from water without releasing any problematic chemical residue,” says study co-author Nirupam Aich, PhD, assistant professor of environmental engineering at the UB School of Engineering and Applied Sciences. “The aerogels we’ve created hold their structure when put in water treatment systems, and they can be applied in diverse water treatment applications.”

An April 14, 2021 UB news release (also on EurekAlert) by Melvin Bankhead III, which originated the news item, explains the breakthrough in more detail,

An aerogel is a light, highly porous solid formed by replacement of liquid in a gel with a gas so that the resulting solid is the same size as the original. They are similar in structural configuration to Styrofoam: very porous and lightweight, yet strong and resilient.

Graphene is a nanomaterial formed by elemental carbon and is composed of a single flat sheet of carbon atoms arranged in a repeating hexagonal lattice.

To create the right consistency of the graphene-based ink, the researchers looked to nature. They added to it two bio-inspired polymers — polydopamine (a synthetic material, often referred to as PDA, that is similar to the adhesive secretions of mussels), and bovine serum albumin (a protein derived from cows).

In tests, the reconfigured aerogel removed certain heavy metals, such as lead and chromium, that plague drinking water systems nationwide. It also removed organic dyes, such as cationic methylene blue and anionic Evans blue, as well as organic solvents like hexane, heptane and toluene.

To demonstrate the aerogel’s reuse potential, the researchers ran organic solvents through it 10 times. Each time, it removed 100% of the solvents. The researchers also reported the aerogel’s ability to capture methylene blue decreased by 2-20% after the third cycle.

The aerogels can also be scaled up in size, Aich says, because unlike nanosheets, aerogels can be printed in larger sizes. This eliminates a previous problem inherent in large-scale production, and makes the process available for use in large facilities, such as in wastewater treatment plants, he says. He adds the aerogels can be removed from water and reused in other locations, and that they don’t leave any kind of residue in the water.

Aich is part of a collaboration between UB and the University of Pittsburgh, led by UB chemistry professor Diana Aga, PhD, to find methods and tools to degrade per- and polyfluoroalkyl substances (PFAS), toxic materials so difficult to break down that they are known as “forever chemicals.” Aich notes the similarities to his work with 3D aerogels, and he hopes results from the two projects can be brought together to create more effective methods of removing waterborne contaminants.

“We can use these aerogels not only to contain graphene particles but also nanometal particles which can act as catalysts,” Aich says. “The future goal is to have nanometal particles embedded in the walls and the surface of these aerogels and they would be able to degrade or destroy not only biological contaminants, but also chemical contaminants.”

Aich, Chi, and Masud [Arvid Masud, PhD] hold a pending patent for the graphene aerogel described in the study, and they are looking for industrial partners to commercialize this process.

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

Emerging investigator series: 3D printed graphene-biopolymer aerogels for water contaminant removal: a proof of concept by Arvid Masud, Chi Zhoub and Nirupam Aich. Environ. Sci.: Nano, 2021,8, 399-414 DOI: https://doi.org/10.1039/D0EN00953A First published online: 09 Dec 2020

This paper is behind a paywall.

Uniting oil and water for a manufacturing-friendly approach to gel production

This is a newish type of gel for which a new manufacturing has been developed jointly by the US National Institute of Standards and Technology (NIST) and the University of Delaware as described in a February 11, 2021 news item on phys.org (Note: A link has been removed),

Oil and water may not mix, but adding the right nanoparticles to the recipe can convert these two immiscible fluids into an exotic gel with uses ranging from batteries to water filters to tint-changing smart windows. A new approach to creating this unusual class of soft materials could carry them out of the laboratory and into the marketplace.

Scientists at the National Institute of Standards and Technology (NIST) and the University of Delaware have found what appears to be a better way to create these gels, which have been an area of intense research focus for more than a decade. Part of their potentially broad utility is the complex set of interconnected microscopic channels that form within them, creating a spongelike structure. These channels not only offer passageways for other materials to travel through, making them useful for filtration, but also give the gel a high amount of internal surface area, a characteristic valuable for speeding up chemical reactions or as scaffolding on which living tissue can grow.

..

It seems they have great hopes for what they’ve called ‘SeedGel’, if this image is anything to go by,

Unlike other gel-creation approaches, where nanoparticles remain at the interface between the gel’s two constituent solvents (top left), the new approach concentrates nanoparticles in the interior of one of the solvents (top right), giving the resulting “SeedGel” unusual mechanical strength. The method could lead to gels that could be manufactured at industrial scales for a wide variety of potential applications. Credit: N. Hanacek / NIST

A February 10, 2021 NIST news release (also on EurekAlert), which originated the news item, delves further into the topic,

While these and other advantages make it sound like gel innovators have struck oil, their creations have not yet mixed well with the marketplace. The gels are commonly formed of two liquid solvents mingled together. As with oil and water, these solvents do not mix well, but to prevent them from completely separating, researchers add custom-designed nanoparticles that can stay at the interface between them. Carefully cooking these ingredients allows a cohesive gel to form. However, the process is demanding because custom-designing nanoparticles for each application has been difficult, and forming the gels has required carefully controlled rapid temperature change. These constraints have made it hard to create this type of gel in any more than small quantities suitable for lab experiments rather than on an industrial scale.

As described in a new Nature Communications paper, the NIST/Delaware team has found ways to sidestep many of these problems. Its novel approach forms what the researchers refer to as a “SeedGel,” an abbreviation for “solvent segregation driven gel.” Instead of designing nanoparticles to remain at the interface between the two solvents, their chosen particles concentrate within one of them. While these particles tend to repel one another, the particles’ affinity toward one of the solvents is stronger and keeps them together in the channel. Using neutron scattering tools at the NIST Center for Neutron Research (NCNR), the team unambiguously proved that it had succeeded at concentrating the nanoparticles where it wanted. 

The resulting gel could be far easier to create, as its two solvents are essentially oil and water, and its nanoparticles are silicon dioxide — essentially tiny spheres of common quartz. It also could have a variety of industrial uses. 

“Our SeedGel has great mechanical strength, it’s much easier to make, and the process is scalable to what manufacturers would need,” said Yun Liu, who is both an NCNR scientist and an affiliated full professor at the University of Delaware. “Plus it’s thermo-reversible.”

This reversibility refers to an optical property that the finished SeedGel possesses: It can switch from transparent to opaque and back again, just by changing its temperature. This property could be harnessed in smart windows that sandwich a thin layer of the gel between two panes of glass.

“This optical property could make the SeedGel useful in other light-sensitive applications as well,” said Yuyin Xi, a researcher from the University of Delaware also working at the NCNR. “They could be useful in sensors.”

Because the team’s gel-creation approach could be used with other solvent-and-nanoparticle combinations, it could become useful in filters for water purification and possibly other filtration processes depending on what type of nanoparticles are used.

Liu also said that the creation approach allows for the size of the channels within the gel to be tuned by changing the rate at which the temperature changes during the formation process, offering application designers another degree of freedom to explore.

“Ours is a generic approach working for many different nanoparticles and solvents,” he said. “It greatly extends the applications of these sorts of gels.”

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

Tunable thermo-reversible bicontinuous nanoparticle gel driven by the binary solvent segregation by Yuyin Xi, Ronald S. Lankone, Li-Piin Sung & Yun Liu. Nature Communications volume 12, Article number: 910 (2021) DOI: https://doi.org/10.1038/s41467-020-20701-3 Published: 10 February 2021

This is paper is open access.

Graphene increases its market penetration in 2025?

It seems that I’m not the only one wondering if the European Union’s gamble (1B Euros paid out over 10 years through a research initiative known as the Graphene Flagship) will pay off. A January 25, 2021 news item on Nanowerk announced a study on that topic (Note: A link has been removed),

What happened to the promised applications of graphene and related materials? Thanks to initiatives like the European Union’s Graphene Flagship and heavy investments by leading industries, graphene manufacturing is mature enough to produce prototypes and some real-life niche applications. Now, researchers at Graphene Flagship partner The Fraunhofer Institute for Systems and Innovation Research (ISI) in Karlsruhe, Germany, have published two papers that roadmap the expected future mass introduction of graphene and related materials in the market.

The January 25, 2021 Graphene Flagship press release (also on EurekAlert), which originated the news item, suggests the gamble will pay off,

Back in 2004, graphene was made by peeling off atomically thin layers from a graphite block. Now, thanks to the advances pioneered by the Graphene Flagship, among others, we can produce high quantities of graphene with a reliable and reproducible quality. Furthermore, the Graphene Flagship has driven the discovery of thousands of layered materials, complementary to graphene in properties and applications, and has spearheaded efforts to standardise the fabrication of graphene to ensure consistency and trustworthiness.

The new publications by Graphene Flagship researchers at Fraunhofer ISI, just issued by IOP Publishing’s journal 2D Materials, review the latest outcomes of the Technology and Innovation Roadmap, a process that explores the different pathways towards industrialisation and commercialisation of graphene and related materials. In particular, these articles summarise the impact that graphene and related materials will have transforming the manufacturing process and triggering the emergence of new value chains.

“Our final goal is seeing graphene and related materials fully integrated in day-to-day products and manufacturing,” says Henning Döscher from Graphene Flagship partner Fraunhofer ISI, who leads the Graphene Flagship Roadmap Team. “We are continuously analysing scientific and technological advances in the field as well as their capacity to fulfil future industrial needs. Our first Graphene Roadmap Brief articles summarise some of the most exciting results,” he adds. “Graphene and related materials add value throughout the value chain, from enhancing and enabling new materials to improving individual components and, eventually, end products.” The most immediate applications of graphene, such as composites, inks and coatings are already commercially available, as highlighted by the Graphene Flagship product gallery. The industry will soon be ready to absorb and implement the latest innovations and start manufacturing batteries, solar panels, electronics, photonic and communication devices and medical technologies.

“The market demand for graphene has almost quadrupled in the last two years,” explains Thomas Reiss from Graphene Flagship partner Fraunhofer ISI, and co-leader of the roadmap endeavour. “By strengthening standards and creating tailored high-quality materials, we expect to go beyond niche products and applications to broad market penetration by 2025,” he adds. “Then, graphene could be incorporated in ubiquitous commodities such as tyres, batteries and electronics.”

The dawning decade seems decisive in the road to market of graphene and related materials. “By 2030 we will see if graphene is really as disruptive as silicon or steel,” says Döscher. “The Graphene Flagship has already shown that graphene is useful for numerous applications,” he adds. “Now, we need to ensure that Europe stays a leader in the field, to ensure we benefit from the economic and societal impact of developing such an innovation.”

Alexander Tzalenchuk, Graphene Flagship Leader for Industrialisation, says: “The publication of the Graphene Flagship Roadmap Briefs is a timely and welcome development for industries innovating with graphene and related materials. Improving trust and confidence in graphene-enabled products is a key prerequisite for industrial uptake. Informed by the market analysis and technology assessment of the Graphene Flagship Roadmap, this further contributes to our agenda providing expert validation of the characteristics of graphene and related materials, graphene-enhanced components, devices and systems, by developing consensus-based and accepted international standards.”

Kari Hjelt, Head of Innovation of the Graphene Flagship, adds: “We see a strong increased interest in graphene by several branches of industry as witnessed by the eleven Spearhead Projects of the Graphene Flagship, all led by industry partners. The first mass applications pave the way to emerging high value-added areas in electronics and biomedical applications. In the near future, we will start to witness the transformative power of graphene in many industries. The updates from the Technology and Innovation Roadmap team sheds light on the road ahead for both research and industrial communities alike.”

It’s hard not to notice that those with the most to gain (Graphene Flagship) are claiming success. That said, the two roadmap briefs are being made freely available and I imagine knowledgeable parties will be happy to offer critiques,

Graphene Roadmap Briefs (No. 1): Innovation interfaces of the Graphene Flagship by Henning Döscher and Thomas Reiß. 2D Materials, Volume 8 DOI: https://iopscience.iop.org/article/10.1088/2053-1583/abddcc Accepted Manuscript online 20 January 2021 • © 2020 IOP Publishing Ltd

Graphene Roadmap Briefs (No. 2): Industrialization status and prospects 2020 by Henning Döscher, Thomas Schmaltz, Christoph Neef, Axel Thielmann, and Thomas Reiß. 2D Materials, Volume 8; DOI: https://iopscience.iop.org/article/10.1088/2053-1583/abddcd Accepted Manuscript online 20 January 2021 • © 2020 IOP Publishing Ltd

Both of these papers are open access.

Rafts! a game for your inner genetic engineer

Earlier this week, RaftsTheGame (@TheRaftsGame) popped up on my twitter feed, which was excellent timing since it’s getting close to Christmas in a year (2020) when I imagine a lot of people may be home and inclined to play games.

The people (rafts4biotech) who produced Rafts The Game (also called Rafts!) are involved in a research project funded by the European Union’s Horizon 2020 programme,

RAFTS!
Create the bacterium of your dreams

Have you ever wondered what it would be like to be a genetic engineer? Now’s your chance to find out! Rafts! is a card game in which your aim is to design a bacterium while trying to overcome the challenges of research work.

If you are a researcher, look no further – Rafts! enables you to finally share your academic struggles with those friends who don’t have a clue of what you do!

THE GAME

In Rafts! you race to become the first scientist to create a bacterium that can do incredible things: cleaning an oil spill, detecting toxic compounds, producing blood for donations… Sounds like science fiction? More like a regular day at the lab!

But don’t get carried away – nobody said conducting research was easy! Hard work alone isn’t enough if you don’t have the right genetic instructions as well as a combination of money, time as well as food for your bacterium. You’ll have to collect all of these resources to finish the masterpiece that is your bacterium.

In this laboratory people play dirty, so don’t forget to keep an eye on your colleagues – they are all trying to achieve their objectives, and sometimes you will compete for the same resources. Don’t hesitate to strike back!

THE CARDS

There are three types of cards in Rafts!: action cards help you gather the resource cards that you will need to achieve the goal in your objective card. Bring your mouse on top of a card to know what it can do!

GET YOURS

Ready to become the biotech wizard you’ve always wanted to be? You’re just a click away from building the bacterium of a lifetime!

Download Rafts! for free and print it yourself – or let your local print shop do it for you:

DOWNLOAD

DESCARGA

Order a ready-made Rafts! deck to your doorsteps – by clicking on the link we direct you to the card shop where you can finish your order:

ORDER

Here’s what the cards look like,

[downloaded from http://www.raftsthegame.com/]

The rules of the game are here.

For anyone curious about the source for the game, here’s a bit about rafts4biotech, from the homepage,

Engineering bacterial lipid rafts to optimise industrial processes

Context

Bacteria are used in the biotechnology industry to produce a wide range of valuable compounds. However, the performance of these microorganisms in the demanding industrial conditions is limited by the toxicity of some compounds and the complex metabolic interactions that occur within the bacterial cells.

Challenge

Generating new synthetic microorganisms that will solve productivity hurdles and yield a great variety of economy-value compounds. These modified strains will be used as standardised microbial chassis platforms to fit industry needs.

Solution

The R4B solution relies on confining the production of compounds to specific areas of the microbe’s membrane called lipid rafts.  This recently-discovered regions present an ideal setting that will avoid interferences with bacterial metabolism and viability.

Given that at least one of the COVID-19 vaccines (Pfizer-BioNTech?) is wrapped in lipid nanobodies and, now, with this mention of lipids, it seemed like a good idea (for me) to learn about lipids. Here’s what I found in the definition for lipid in The free Dictionary,

a group of substances comprising fatty, greasy, oily, and waxy compounds that are insoluble in water and soluble in nonpolar solvents, such as hexane, ether, and chloroform.

Let the games begin!

Boost single-walled carbon nantube (SWCNT) production

I’m fascinated by this image,

Caption: Skoltech researchers have investigated the procedure for catalyst delivery used in the most common method of carbon nanotube production, chemical vapor deposition (CVD), offering what they call a “simple and elegant” way to boost productivity and pave the way for cheaper and more accessible nanotube-based technology. Credit: Pavel Odinev/Skoltech

If I understand it correctly, getting the catalyst particles into a tighter, more uniform formation is what could lead to a boost in the production of single-walled carbon nanotubes (SWCNTs).

The work was announced in a Nov. 30, 2020 news item in Nanowerk,

Skoltech [Skolkovo Institute of Science and Technology; Russia] researchers have investigated the procedure for catalyst delivery used in the most common method of carbon nanotube production, chemical vapor deposition (CVD), offering what they call a “simple and elegant” way to boost productivity and pave the way for cheaper and more accessible nanotube-based technology.

A Nov. 30, 2020 Skolkovo Institute of Science and Technology (Skoltech) press release (also on EurekAlert but published on Dec. 1, 2020), which originated the news item, explains in detail,

Single-walled carbon nanotubes (SWCNT), tiny rolled sheets of graphene with a thickness of just one atom, hold huge promise when it comes to applications in materials science and electronics. That is the reason why so much effort is focused on perfecting the synthesis of SWCNTs; from physical methods, such as using laser beams to ablate a graphite target, all the way to the most common CVD approach, when metal catalyst particles are used to “strip” a carbon-containing gas of its carbon and grow the nanotubes on these particles.

“The road from raw materials to carbon nanotubes requires a fine balance between dozens of reactor parameters. The formation of carbon nanotubes is a tricky and complex process that has been studied for a long time, but still keeps many secrets,” explains Albert Nasibulin, a professor at Skoltech and an adjunct professor at the Department of Chemistry and Materials Science, Aalto University School of Chemical Engineering.

Various ways of enhancing catalyst activation, in order to produce more SWCNTs with the required properties, have already been suggested. Nasibulin and his colleagues focused on the injection procedure, namely on how to distribute ferrocene vapor (a commonly used catalyst precursor) within the reactor.

They grew their carbon nanotubes using the aerosol CVD approach, using carbon monoxide as a source of carbon, and monitored the synthesis productivity and SWCNT characteristics (such as their diameter) depending on the rate of catalyst injection and the concentration of CO2 (carbon dioxide; used as an agent for fine-tuning). Ultimately the researchers concluded that “injector flow rate adjustment could lead to a 9-fold increase in the synthesis productivity while preserving most of the SWCNT characteristics”, such as their diameter, the share of defective nanotubes, and film conductivity.

“Every technology is always about efficiency. When it comes to CVD production of nanotubes, the efficiency of the catalyst is usually out of sight. However, we see a great opportunity there and this work is only a first step towards an efficient technology,” Dmitry Krasnikov, senior research scientist at Skoltech and co-author of the paper, says.

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

Activation of catalyst particles for single-walled carbon nanotube synthesis by Eldar M.Khabushev, Julia V. Kolodiazhnaia, Dmitry V. Krasnikov, Albert G. Nasibulin. Chemical Engineering Journal DOI: https://doi.org/10.1016/j.cej.2020.127475 Available online 24 October 2020, 127475

This paper is behind a paywall.

OCSiAl becomes largest European supplier of single-walled carbon nanotubes (SWCNTs)

It’s time I posted news about OCSiAl as it’s been about five years since they were last mentioned here. An April 24, 2020 news item on AzoNano proclaims a new status for the company,

As from [sic] April 2020, OCSiAl is able to commercialize up to 100 tonnes annually of its TUBALL™ single wall carbon nanotubes [single-walled carbon nanotubes or SWCNTs] in Europe thanks to the company’s upgraded dossier under the EU’s [European Union’s] “Registration, Evaluation, Authorization and Restriction of Chemicals” (REACH) legislation, being additionally compliant with the new Annexes on nanoforms. OCSiAl will continue to expand markets for nanotubes and widen industrial applications by scaling-up its permitted volume in Australia and Canada in 2020, pending approval by the authorities.

An April 23, 2020 OCSiAl press release, which originated the news item, provides more details about the company and its customers in ‘marketingese’ (marketing language),

OCSiAl is now the only company in Europe able to commercialize up to 100 tonnes of single wall carbon nanotubes, also known as graphene nanotubes. This step allows the company to boost its presence in the region and to meet the growing market demand for industrial volumes of graphene nanotubes. The company’s current portfolio includes over 1,600 customers worldwide, with China and Europe as the two most rapidly expanding markets for nanotube applications in transportation, electronics, construction, infrastructure, renewable energy, power sources, sports equipment, 3D-printing, textiles, sensors and many more.

OCSiAl plays a leading role in improving the accessibility of information on the nature of graphene nanotubes and in forming the principles of their safe handling – the company has so far initiated 16 studies in these fields, including those required by the revised REACH annex. TUBALL nanotubes demonstrate no skin irritation, corrosion or sensitization, no mutagenic effect, and no adverse effect on reproductive toxicity. In addition, ecotoxicity studies have shown no toxic effect on Daphnia or algae. The typical exposure values of respirable fraction of TUBALL in the workplace is much less than 5% of the Recommended Exposure Limits (REL) as per NIOSH in the USA, which is of practical importance for manufacturers working with nanotubes. And end users can also be reassured that these studies have shown that no TUBALL nanotubes are released during utilization of products made with nanoaugmented materials. All these findings reflect the unique nature and morphology of TUBALL graphene nanotubes.

OCSiAl continues to accelerate the acceptance of this unique material in various markets by supplying high-quality nanotubes at an economically feasible price and in industrial volumes. TUBALL is regulated by the Environmental Protection Agency (EPA) in the US, where it is also allowed to be commercialized in industrial volumes. The company’s near-term plans include scaling-up the permitted volume of industrial commercialization of graphene nanotubes in Australia and Canada.

The company appears to be trying to rebrand carbon nanotubes as graphene nanotubes. It can be done (e.g., facial tissue instead of Kleenex or photocopy instead of Xerox) but it can take a long time and, after a brief search (May 13, 2020), I was not able to find any other reference to ‘graphene nanotubes’ online.

Between the two of them, OCSiAl’s Wikipedia entry and the company’s Team webpage (scroll down past the smiling faces), you can find some company history.

Graphene from gum trees

Caption: Eucalyptus bark extract has never been used to synthesise graphene sheets before. Courtesy: RMIT University

It’s been quite educational reading a June 24, 2019 news item on Nanowerk about deriving graphene from Eucalyptus bark (Note: Links have been removed),

Graphene is the thinnest and strongest material known to humans. It’s also flexible, transparent and conducts heat and electricity 10 times better than copper, making it ideal for anything from flexible nanoelectronics to better fuel cells.

The new approach by researchers from RMIT University (Australia) and the National Institute of Technology, Warangal (India), uses Eucalyptus bark extract and is cheaper and more sustainable than current synthesis methods (ACS Sustainable Chemistry & Engineering, “Novel and Highly Efficient Strategy for the Green Synthesis of Soluble Graphene by Aqueous Polyphenol Extracts of Eucalyptus Bark and Its Applications in High-Performance Supercapacitors”).

A June 24, 2019 RMIT University news release (also on EurekAlert), which originated the news item, provides a little more detail,

RMIT lead researcher, Distinguished Professor Suresh Bhargava, said the new method could reduce the cost of production from $USD100 per gram to a staggering $USD0.5 per gram.

“Eucalyptus bark extract has never been used to synthesise graphene sheets before and we are thrilled to find that it not only works, it’s in fact a superior method, both in terms of safety and overall cost,” said Bhargava.

“Our approach could bring down the cost of making graphene from around $USD100 per gram to just 50 cents, increasing it availability to industries globally and enabling the development of an array of vital new technologies.”

Graphene’s distinctive features make it a transformative material that could be used in the development of flexible electronics, more powerful computer chips and better solar panels, water filters and bio-sensors.

Professor Vishnu Shanker from the National Institute of Technology, Warangal, said the ‘green’ chemistry avoided the use of toxic reagents, potentially opening the door to the application of graphene not only for electronic devices but also biocompatible materials.

“Working collaboratively with RMIT’s Centre for Advanced Materials and Industrial Chemistry we’re harnessing the power of collective intelligence to make these discoveries,” he said.

A novel approach to graphene synthesis:

Chemical reduction is the most common method for synthesising graphene oxide as it allows for the production of graphene at a low cost in bulk quantities.

This method however relies on reducing agents that are dangerous to both people and the environment.

When tested in the application of a supercapacitor, the ‘green’ graphene produced using this method matched the quality and performance characteristics of traditionally-produced graphene without the toxic reagents.

Bhargava said the abundance of eucalyptus trees in Australia made it a cheap and accessible resource for producing graphene locally.

“Graphene is a remarkable material with great potential in many applications due to its chemical and physical properties and there’s a growing demand for economical and environmentally friendly large-scale production,” he said.

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

Novel and Highly Efficient Strategy for the Green Synthesis of Soluble Graphene by Aqueous Polyphenol Extracts of Eucalyptus Bark and Its Applications in High-Performance Supercapacitors by Saikumar ManchalaV. S. R. K. Tandava, Deshetti Jampaiah, Suresh K. Bhargava, Vishnu Shanker. ACS Sustainable Chem. Eng.2019XXXXXXXXXX-XXX DOI: https://doi.org/10.1021/acssuschemeng.9b01506 Publication Date:June 13, 2019

Copyright © 2019 American Chemical Society

This paper is behind a paywall.

Vitamin C helps gold nanowires grow

This research gives new meaning to ‘Take your vitamin C’ as can be seen in a February 19, 2019 news item on Nanowerk,

A boost of vitamin C helped Rice University scientists turn small gold nanorods into fine gold nanowires.

Common, mild ascorbic acid is the not-so-secret sauce that helped the Rice lab of chemist Eugene Zubarev grow pure batches of nanowires from stumpy nanorods without the drawbacks of previous techniques.

“There’s no novelty per se in using vitamin C to make gold nanostructures because there are many previous examples,” Zubarev said. “But the slow and controlled reduction achieved by vitamin C is surprisingly suitable for this type of chemistry in producing extra-long nanowires.”

A February 19, 2019 Rice University news release (also on EurekAlert), which originated the news item, provides more technical detail about the research

The Rice lab’s nanorods are about 25 nanometers thick at the start of the process – and remain that way while their length grows to become long nanowires. Above 1,000 nanometers in length, the objects are considered nanowires, and that matters. The wires’ aspect ratio – length over width – dictates how they absorb and emit light and how they conduct electrons. Combined with gold’s inherent metallic properties, that could enhance their value for sensing, diagnostic, imaging and therapeutic applications.

Zubarev and lead author Bishnu Khanal, a Rice chemistry alumnus, succeeded in making their particles go far beyond the transition from nanorod to nanowire, theoretically to unlimited length.

The researchers also showed the process is fully controllable and reversible. That makes it possible to produce nanowires of any desired length, and thus the desired configuration for electronic or light-manipulating applications, especially those that involve plasmons, the light-triggered oscillation of electrons on a metal’s surface.

The nanowires’ plasmonic response can be tuned to emit light from visible to infrared and theoretically far beyond, depending on their aspect ratios.

The process is slow, so it takes hours to grow a micron-long nanowire. “In this paper, we only reported structures up to 4 to 5 microns in length,” Zubarev said. “But we’re working to make much longer nanowires.”

The growth process only appeared to work with pentahedrally twinned gold nanorods, which contain five linked crystals. These five-sided rods — “Think of a pencil, but with five sides instead of six,” Zubarev said — are stable along the flat surfaces, but not at the tips.

“The tips also have five faces, but they have a different arrangement of atoms,” he said. “The energy of those atoms is slightly lower, and when new atoms are deposited there, they don’t migrate anywhere else.”

That keeps the growing wires from gaining girth. Every added atom increases the wire’s length, and thus the aspect ratio.

The nanorods’ reactive tips get help from a surfactant, CTAB, that covers the flat surfaces of nanorods. “The surfactant forms a very dense, tight bilayer on the sides, but it cannot cover the tips effectively,” Zubarev said.

That leaves the tips open to an oxidation or reduction reaction. The ascorbic acid provides electrons that combine with gold ions and settle at the tips in the form of gold atoms. And unlike carbon nanotubes in a solution that easily aggregate, the nanowires keep their distance from one another.

“The most valuable feature is that it is truly one-dimensional elongation of nanorods to nanowires,” Zubarev said. “It does not change the diameter, so in principal we can take small rods with an aspect ratio of maybe two or three and elongate them to 100 times the length.”
He said the process should apply to other metal nanorods, including silver.

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

Chemical Transformation of Nanorods to Nanowires: Reversible Growth and Dissolution of Anisotropic Gold Nanostructures by Bishnu P. Khanal and Eugene R. Zubarev. ACS Nano, 2019, 13 (2), pp 2370–2378 DOI: 10.1021/acsnano.8b09203 Publication Date (Web): February 12, 2019

Copyright © 2019 American Chemical Society

This paper is behind a paywall. Below you’ll find an image fo what I believe to be the vitamin C-enhanced gold nanowires.

Caption: Gold nanowires grown in the Rice University lab of chemist Eugene Zubarev promise to provide tunable plasmonic properties for optical and electronic applications. The wires can be controllably grown from nanorods, or reduced. Credit: Zubarev Research Group/Rice University

Altered virus spins gold into beads

They’re not calling this synthetic biology but I’ m pretty sure that altering a virus gene so the virus can spin gold (Rumpelstiltskin anyone?) qualifies. From an August 24, 2018 news item on ScienceDaily,

The race is on to find manufacturing techniques capable of arranging molecular and nanoscale objects with precision.

Engineers at the University of California, Riverside, have altered a virus to arrange gold atoms into spheroids measuring a few nanometers in diameter. The finding could make production of some electronic components cheaper, easier, and faster.

An August 23, 2018 University of California at Riverside (UCR) news release (also on EurekAlett) by Holly Ober, which originated the news item, adds detail,

“Nature has been assembling complex, highly organized nanostructures for millennia with precision and specificity far superior to the most advanced technological approaches,” said Elaine Haberer, a professor of electrical and computer engineering in UCR’s Marlan and Rosemary Bourns College of Engineering and senior author of the paper describing the breakthrough. “By understanding and harnessing these capabilities, this extraordinary nanoscale precision can be used to tailor and build highly advanced materials with previously unattainable performance.”

Viruses exist in a multitude of shapes and contain a wide range of receptors that bind to molecules. Genetically modifying the receptors to bind to ions of metals used in electronics causes these ions to “stick” to the virus, creating an object of the same size and shape. This procedure has been used to produce nanostructures used in battery electrodes, supercapacitors, sensors, biomedical tools, photocatalytic materials, and photovoltaics.

The virus’ natural shape has limited the range of possible metal shapes. Most viruses can change volume under different scenarios, but resist the dramatic alterations to their basic architecture that would permit other forms.

The M13 bacteriophage, however, is more flexible. Bacteriophages are a type of virus that infects bacteria, in this case, gram-negative bacteria, such as Escherichia coli, which is ubiquitous in the digestive tracts of humans and animals. M13 bacteriophages genetically modified to bind with gold are usually used to form long, golden nanowires.

Studies of the infection process of the M13 bacteriophage have shown the virus can be converted to a spheroid upon interaction with water and chloroform. Yet, until now, the M13 spheroid has been completely unexplored as a nanomaterial template.

Haberer’s group added a gold ion solution to M13 spheroids, creating gold nanobeads that are spiky and hollow.

“The novelty of our work lies in the optimization and demonstration of a viral template, which overcomes the geometric constraints associated with most other viruses,” Haberer said. “We used a simple conversion process to make the M13 virus synthesize inorganic spherical nanoshells tens of nanometers in diameter, as well as nanowires nearly 1 micron in length.”

The researchers are using the gold nanobeads to remove pollutants from wastewater through enhanced photocatalytic behavior.

The work enhances the utility of the M13 bacteriophage as a scaffold for nanomaterial synthesis. The researchers believe the M13 bacteriophage template transformation scheme described in the paper can be extended to related bacteriophages.

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

M13 bacteriophage spheroids as scaffolds for directed synthesis of spiky gold nanostructures by Tam-Triet Ngo-Duc, Joshua M. Plank, Gongde Chen, Reed E. S. Harrison, Dimitrios Morikis, Haizhou Liu, and Elaine D. Haberer. Nanoscale, 2018,10, 13055-13063 DOI: 10.1039/C8NR03229G First published on 25 Jun 2018

This paper is behind a paywall.

For another example of genetic engineering and synthetic biology, see my July 18, 2018 posting: Genetic engineering: an eggplant in Bangladesh and a synthetic biology grant at Concordia University (Canada).

For anyone unfamiliar with the Rumpelstiltskin fairytale about spinning straw into gold, see its Wikipedida entry.

Researchers, manufacturers, and administrators need to consider shared quality control challenges to advance the nanoparticle manufacturing industry ‘

Manufacturing remains a bit of an issue where nanotechnology is concerned due to the difficulties of producing nanoparticles of a consistent size and type,


Electron micrograph showing gallium arsenide nanoparticles of varying shapes and sizes. Such heterogeneity [variation]  can increase costs and limit profits when making nanoparticles into products. A new NIST study recommends that researchers, manufacturers and administrators work together to solve this, and other common problems, in nanoparticle manufacturing. Credit: A. Demotiere, E. Shevchenko/Argonne National Laboratory

The US National Institute of Standards and Technology (NIST) has produced a paper focusing on how nanoparticle manufacturing might become more effective, from an August 22, 2018 news item on ScienceDaily,

Nanoparticle manufacturing, the production of material units less than 100 nanometers in size (100,000 times smaller than a marble), is proving the adage that “good things come in small packages.” Today’s engineered nanoparticles are integral components of everything from the quantum dot nanocrystals coloring the brilliant displays of state-of-the-art televisions to the miniscule bits of silver helping bandages protect against infection. However, commercial ventures seeking to profit from these tiny building blocks face quality control issues that, if unaddressed, can reduce efficiency, increase production costs and limit commercial impact of the products that incorporate them.

To help overcome these obstacles, the National Institute of Standards and Technology (NIST) and the nonprofit World Technology Evaluation Center (WTEC) advocate that nanoparticle researchers, manufacturers and administrators “connect the dots” by considering their shared challenges broadly and tackling them collectively rather than individually. This includes transferring knowledge across disciplines, coordinating actions between organizations and sharing resources to facilitate solutions.

The recommendations are presented in a new paper in the journal ACS Applied Nano Materials.

An August 22, 2018 NIST news release, which originated the news item, describes how the authors of the ACS [American Chemical Society) Applied Nano Materials paper developed their recommendations,

“We looked at the big picture of nanoparticle manufacturing to identify problems that are common for different materials, processes and applications,” said NIST physical scientist Samuel Stavis, lead author of the paper. “Solving these problems could advance the entire enterprise.”

The new paper provides a framework to better understand these issues. It is the culmination of a study initiated by a workshop organized by NIST that focused on the fundamental challenge of reducing or mitigating heterogeneity, the inadvertent variations in nanoparticle size, shape and other characteristics that occur during their manufacture.

“Heterogeneity can have significant consequences in nanoparticle manufacturing,” said NIST chemical engineer and co-author Jeffrey Fagan.

In their paper, the authors noted that the most profitable innovations in nanoparticle manufacturing minimize heterogeneity during the early stages of the operation, reducing the need for subsequent processing. This decreases waste, simplifies characterization and improves the integration of nanoparticles into products, all of which save money.

The authors illustrated the point by comparing the production of gold nanoparticles and carbon nanotubes. For gold, they stated, the initial synthesis costs can be high, but the similarity of the nanoparticles produced requires less purification and characterization. Therefore, they can be made into a variety of products, such as sensors, at relatively low costs.

In contrast, the more heterogeneous carbon nanotubes are less expensive to synthesize but require more processing to yield those with desired properties. The added costs during manufacturing currently make nanotubes only practical for high-value applications such as digital logic devices.

“Although these nanoparticles and their end products are very different, the stakeholders in their manufacture can learn much from each other’s best practices,” said NIST materials scientist and co-author J. Alexander Liddle. “By sharing knowledge, they might be able to improve both seemingly disparate operations.”

Finding ways like this to connect the dots, the authors said, is critically important for new ventures seeking to transfer nanoparticle technologies from laboratory to market.

“Nanoparticle manufacturing can become so costly that funding expires before the end product can be commercialized,” said WTEC nanotechnology consultant and co-author Michael Stopa. “In our paper, we outlined several opportunities for improving the odds that new ventures will survive their journeys through this technology transfer ‘valley of death.’”

Finally, the authors considered how manufacturing challenges and innovations are affecting the ever-growing number of applications for nanoparticles, including those in the areas of electronics, energy, health care and materials.

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

Nanoparticle Manufacturing – Heterogeneity through Processes to Products by Samuel M. Stavis, Jeffrey A. Fagan, Michael Stopa, and J. Alexander Liddle. ACS Appl. Nano Mater., Article ASAP DOI: 10.1021/acsanm.8b01239 Publication Date (Web): August 16, 2018

Copyright © 2018 American Chemical Society

This paper is behind a paywall.

I looked at this paper briefly and found it to give a good overview. The focus is on manufacturing and making money. I imagine any discussion about the life cycle of the materials and possible environmental and health risks would have been considered ‘scope creep’.

I have two postings that provide additional information about manufacturing concerns, my February 10, 2014 posting:  ‘Valley of Death’, ‘Manufacturing Middle’, and other concerns in new government report about the future of nanomanufacturing in the US and my September 5, 2016 posting: An examination of nanomanufacturing and nanofabrication.