Tag Archives: cellulose nanofibrils (CNF)

Cellulose-based wound sutures

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Caption: Advancing Surgical Sutures: The Promise of Cellulose-Based Materials. Credit: CAS Key Laboratory of Biobased Materials, Qingdao New Energy Shandong Laboratory, System Integration Engineering Center, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China

A January 22, 2025 Journal of Bioresources and Bioproducts news release on EurekAlert announces a review of cellulose-based (including nanocellulose) wound sutures,

A recent review published in the Journal of Bioresources and Bioproducts examines the state of cellulose-based sutures, focusing on materials, fabrication methods, and application performance. The study underscores the potential of these sutures as eco-friendly alternatives to traditional synthetic sutures, with significant advancements in biocompatibility and biodegradability.

Surgical sutures are critical in wound closure and healing, with traditional materials like cotton and synthetic polymers dominating the market. However, the rise of sustainable and biocompatible materials has led researchers to explore cellulose-based sutures as a viable alternative. A comprehensive review published in the Journal of Bioresources and Bioproducts provides an in-depth look at the current state of cellulose-based sutures, their fabrication methods, and potential applications.

Cellulose, the most abundant natural polymer on Earth, offers several advantages for surgical sutures, including non-toxicity, biocompatibility, and mechanical strength. The review covers various types of cellulose-based sutures, including natural cellulose, nanocellulose, and regenerated cellulose. Each type offers unique properties, with nanocellulose showing particular promise due to its high strength and flexibility. For instance, cellulose nanofibrils (CNF) have been used to create sutures with tensile strengths comparable to traditional materials, while maintaining excellent biocompatibility.

The review also highlights innovative fabrication methods such as wet spinning and interfacial polyelectrolyte complexation (IPC) spinning. Wet spinning is a traditional method used to create strong and flexible fibers, while IPC spinning allows for the creation of composite fibers with enhanced properties. These methods enable the production of sutures with tailored mechanical properties, biodegradability, and antibacterial characteristics.

One of the key challenges identified in the review is the need for consistent quality and improved biocompatibility in cellulose-based sutures. While natural cellulose fibers like cotton have been used historically, their quality can vary, leading to inconsistent performance. In contrast, nanocellulose and oxidized regenerated cellulose (ORC) offer more uniform properties and can be engineered for specific applications. For example, ORC sutures have demonstrated significant biodegradability, losing over 50% of their strength within 14 days, making them suitable for absorbable sutures.

The review also emphasizes the importance of multifunctional sutures that integrate antibacterial properties and growth factors to enhance wound healing. For instance, CNF/chitosan composite sutures have shown excellent antibacterial activity against common pathogens like Escherichia coli and Staphylococcus aureus, while maintaining high cell viability in vitro and in vivo.

Looking ahead, the review suggests that cellulose-based sutures could become the next generation of high-end medical sutures, driven by advancements in materials science and a growing focus on sustainability. Future research should focus on optimizing fabrication processes, enhancing mechanical properties, and conducting clinical trials to validate their performance.

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

Cellulose-based suture: State of art, challenge, and future outlook by Meiyan Wu, Lei Ding, Xiaoying Bai, Yuxiang Cao, Mehdi Rahmaninia, Bing Li, Bin Li. Journal of Bioresources and Bioproducts Available online 15 December 2024 In Press, Corrected Proof DOI: https://doi.org/10.1016/j.jobab.2024.11.006

This paper is open access.

Reusable ‘sponge’ for soaking up marine oil spills—even in northern waters

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A May 28, 2024 news item on phys.org announces some new research into sponges, a topic of some interest where oil spill cleanups are concerned,

Oil spills, if not cleaned up quickly and effectively, can cause lasting damage to marine and coastal environments. That’s why a team of North American researchers are developing a new sponge-like material that is not only effective at grabbing and holding oil on its surface (adsorption), but can be reused again and again—even in icy Canadian waters….

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A May 27, 2024 Canadian Light Source (CLS) news release (also received via email) by Rowan Hollinger provides some details, Note: CNF can be cellulose nanofibers, cellulose nanofibrils, or, it’s sometimes called, nanofibrillated cellulose (NFC) (see Nanocellulose Wikipedia entry),,

The special material – called CNF-SP aerogel — combines a biodegradable cellulose-based material with a substance called spiropyran, a light-sensitive material. Spiropyran has a unique ‘switchable’ property that allows the aerogel to go between being oil-sorbent and oil-repellent, just like a kitchen sponge that can be used to soak up and squeeze out water.

“Once spiropyran has been added to the aerogel, after each usage we just switch the light condition,” explains Dr. Baiyu Helen Zhang, professor and Canada Research Chair at Memorial University, Newfoundland. “We used the aerogel as an oil sorbent under visible light. After oil adsorption, we switched the light condition to UV light. This switch helped the sponge to release the oil.”

And the material continues soaking up and releasing oil, even when the water temperature drops, according to Dr. Xiujuan Chen, an assistant professor at University of Texas – Arlington.

“We found that when we tested the oil sorbent’s performance under different kinds of environmental conditions, it had a very good performance in a cold environment. This is quite useful for cold winter seasons, particularly for Canada.”

The researchers used the CLS’s Mid-IR beamline to examine the characteristics of the aerogel before and after exposing it to visible and UV light. From here, the researchers are looking to scale up their research with large pilot studies and even testing the material in the field.

“The CLS has very unique infrastructure that supports students and researchers like us to conduct many kinds of very exciting research and to contribute to scientific knowledge and engineering applications,” says Zhang.

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

Development of a spiropyran-assisted cellulose aerogel with switchable wettability as oil sorbent for oil spill cleanup by Hongjie Wang, Xiujuan Chen, Bing Chen, Yuming Zhao, Baiyu Zhang. Science of The Total Environment Volume 923, 1 May 2024, 171451 DOI: https://doi.org/10.1016/j.scitotenv.2024.171451 Available online: 2 March 2024 Version of Record: 8 March 2024

This paper is behind a paywall.

The CLS has made this video of the researchers available,

For the curious, I have many posts about sponges and, in particular, sponges for use in environmental cleanups.

Cellulose nanofibrils for slow-release fertilizer

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An October 17, 2022 news item on phys.org highlights nanocellulose research from Brazil, Note: A link has been removed,

A research team affiliated with the Laboratory of Polymeric Materials and Biosorbents at the Federal University of São Carlos (UFSCar) in Araras, São Paulo state, Brazil, has produced and is testing cellulose-based materials for enhanced-efficiency fertilizers to improve the supply of nutrients to crops and reduce the release of non-biodegradable chemicals [forever chemicals] into the ecosystem.

The studies were led by Roselena Faez, a professor at the Center for Agricultural Sciences (CCA-UFSCar). The findings have recently been reported in two publications. One is an article published in Carbohydrate Polymers, with Débora França as first author. Here [keep scrolling down] the researchers describe how they used modified nanocellulose to discharge the nutrients contained in fertilizer into the soil slowly and in a controlled manner, given that nitrogen, phosphorus and potassium are highly soluble.

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Caption: The first and third photos show the paper made from phosphorylated sugarcane cellulose. The second shows the 3D structure of the material comprising cellulose and nutrient. The fourth shows the microparticles in powder form and after molding into tablets. Credit: Lucas Luiz Messa/Débora França

An October 19, 2022 Fundação de Amparo à Pesquisa do Estado de São Paulo [FAPESP] press release (also on EurekAlert but published October 17, 2022) by Karina Ninni, originated the phys.org news item. The researchers explain (Note: Links have been removed),

“Potassium is rapidly washed away by rain because of its high ion mobility. It’s the hardest to release in a controlled manner. Nitrogen can be obtained from various sources, such as nitrates, ammonia and urea, but plants get the nitrogen they need most easily from nitrate, which is also easily washed away and doesn’t remain in the soil for long. Phosphorus [as phosphate] is a very large ion and less mobile than the other macronutrients,” said Faez, who coordinates the Polymeric Materials and Biosorbents Research Group at UFSCar Araras.

Controlled-release products are available on the market, she added, but most are made of synthetic polymers, which are non-biodegradable. “Fertilizer grains are about the size of grains of coarse sea salt. To make sure the nutrients are released slowly, they’re coated with layers of polymer that last about two months each, so the manufacturer applies two, three or four coats, according to the desired length of time for controlled release,” Faez explained, noting that the polymers in question are plastics and remain in the soil, eventually degrading into microparticles that last virtually forever.

The researchers at UFSCar developed an entirely different product in which the chemical reaction between the modified nanocellulose and mineral salts keeps the nutrients in the soil. “We focused on the worst problems, which are nitrate and potassium. The material we developed is totally biodegradable and releases these nutrients at about the same slow rate as the available synthetic materials,” Faez said.

The nanocellulose was obtained from pure cellulose donated by a paper factory. The nanofibrils were functionalized with positive and negative charges to enhance polymer-nutrient interaction. “Because the salts are also made up of positively or negatively charged particles and highly soluble, we hypothesized that negatively charged nanocellulose would react with positive ions in the salts, while positively charged nanocellulose would interact with negative ions, reducing the solubility of the salts. This proved to be the case, and the group succeeded in modulating nutrient release in accordance with the type of particle in the material,” França said.

Evaluation in soil

The group fabricated the product in the form of tablets and evaluated its performance in terms of nutrient release into the soil. Evaluation of release into water is the usual method, and water is a very different system from soil. This part of the research was conducted in partnership with Claudinei Fonseca Souza, a professor at CCA-UFSCar’s Department of Natural Resources and Environmental Protection in Araras.

“We evaluated nutrient release into the soil and biodegradation of the material at the site for 100 days. But we deliberately used very poor soil with little organic matter, because this enables us to see the physical effects of release more easily,” Faez said.

The researchers used two techniques to obtain tablets: atomization and spray drying to encapsulate the nutrients with the nanocellulose, followed by heat processing of the resulting powder, which was pressed in a mold. This work was completed with the help of colleagues at the Cellulose and Wood Materials Laboratory belonging to EMPA (Swiss Federal Laboratories for Materials Science and Technology) and in collaboration with UFSCar’s Water, Soil and Environment Engineering Research Group, led by Souza. França performed the cellulose modifications at EMPA while on an internship there with support from FAPESP. She was also supported by a doctoral scholarship in Brazil.

Self-fertilization

The second recent article by the group was published in Industrial Crops and Products, with chemist Lucas Luiz Messa as first author. The goal of the study was to extract cellulose from sugarcane bagasse and modify it with a surface negative charge by phosphorylation (addition of a phosphorus group) to allow controlled release of potassium. In theory, delivery of plant nutrition would be slowed by cellulose phosphorylation, which would create surface anionic charges that would bind to macronutrient and micronutrient cations. 

The group prepared three types of structure with the phosphorylated cellulose: oven-dried paper-like film; spray-dried powder; and freeze-dried porous bulk similar to polystyrene foam. Freeze drying, or lyophilization, was seen to leave nutrients in the voids left by water removal. 

“Technologically speaking, the paper-like structure was the best material we produced for controlled delivery of nutrients. Several products can be created using this paper,” Faez said.

The results obtained in the research led by Messa enabled the group to develop small propagation pots for seedling cultivation. When this material degrades, the phosphorus it contains is released. According to Faez, cellulose phosphorylation is cheap, and the cost of the end product is relatively low. “It’s more or less BRL 0.27 per gram of paper produced. The propagation pot must be about 1 gram. Unit cost is therefore about BRL 0.30 in terms of laboratory costs,” she said.

Biodegradable propagation pots are already available on the market. “But our product has built-in fertilizer, which is a major competitive advantage. Indeed, we’ve filed a patent application,” she said.

The pot is about to be trialed by a flower producer in Holambra, São Paulo state. Several batches produced in the laboratory have been shipped there. Nutrient release has so far been tested only in water. “We call this an accelerated ion release assessment method because it’s faster in water, but even in water we found the release rate to be 40%-50% slower compared with the behavior of the ion in the material and without the material. Even in water, therefore, we succeeded in retaining these ions. We assume delivery will be even slower in the substrate,” she said.

The research was also supported by FAPESP via a Doctoral Scholarship in Brazil and a Research Internship Abroad Scholarship awarded to Messa, and a Regular Research Grant awarded to Faez.

Messa was assisted by a colleague at the University of California Davis (USA), where he worked as a research intern.

About São Paulo Research Foundation (FAPESP)

The São Paulo Research Foundation (FAPESP) is a public institution with the mission of supporting scientific research in all fields of knowledge by awarding scholarships, fellowships and grants to investigators linked with higher education and research institutions in the State of São Paulo, Brazil. FAPESP is aware that the very best research can only be done by working with the best researchers internationally. Therefore, it has established partnerships with funding agencies, higher education, private companies, and research organizations in other countries known for the quality of their research and has been encouraging scientists funded by its grants to further develop their international collaboration. You can learn more about FAPESP at www.fapesp.br/en and visit FAPESP news agency at www.agencia.fapesp.br/en to keep updated with the latest scientific breakthroughs FAPESP helps achieve through its many programs, awards and research centers. You may also subscribe to FAPESP news agency at http://agencia.fapesp.br/subscribe

I have links and citations for both papers mentioned in the press release,

Sugarcane bagasse derived phosphorylated cellulose as substrates for potassium release induced by phosphates surface and drying methods by Lucas Luiz Messa, You-Lo Hsieh, Roselena Faez. Industrial Crops and Products Volume 187, Part A, 1 November 2022, 115350 DOI: https://doi.org/10.1016/j.indcrop.2022.115350 Available online 20 July 2022, Version of Record 20 July 2022

This paper is behind a paywall.

Charged-cellulose nanofibrils as a nutrient carrier in biodegradable polymers for enhanced efficiency fertilizers by Débora França, Gilberto Siqueira, Gustav Nyström, Frank Clemens, Claudinei Fonseca Souza, Roselena Faez. Carbohydrate Polymers Volume 296, 15 November 2022, 119934 DOI: https://doi.org/10.1016/j.carbpol.2022.119934 Available online 1 August 2022, Version of Record 3 August 2022

This paper is behind a paywall.

Desalination with nanowood

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A new treatment for wood could make renewable salt-separating membranes. Courtesy: University of Maryland

An August 6, 2019 article by Adele Peters for Fast Company describes a ‘wooden’approach to water desalinization (also known as desalination),

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“We are trying to develop a new type of membrane material that is nature-based,” says Z. Jason Ren, an engineering professor at Princeton University and one of the coauthors of a new paper in Science Advances about that material, which is made from wood. It’s designed for use in a process called membrane distillation, which heats up saltwater and uses pressure to force the water vapor through a membrane, leaving the salt behind and creating pure water. The membranes are usually made from a type of plastic. Using “nanowood” membranes instead can both improve the energy efficiency of the process and avoid the environmental problems of plastic.

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An August 2, 2019 University of Maryland (UMD) news release provides more detail about the research,

A membrane made of a sliver of wood could be the answer to renewably sourced water cleaning. Most membranes that are currently used to distill fresh water from salty are made of polymers based on fossil fuels.

Inspired by the intricate system of water circulating in a tree, a research team from the University of Maryland, Princeton University, and the University of Colorado Boulder have figured out how to use a thin slice of wood as a membrane through which water vapor can evaporate, leaving behind salt or other contaminants.

“This work demonstrates another exciting energy/water application of nanostructured wood, as a high-performance membrane material,” said Liangbing Hu, a professor of materials science and engineering at UMD’s A. James Clark School of Engineering, who co-led the study.

The team chemically treated the wood to become hydrophobic, so that it more efficiently allows water vapor through, driven by a heat source like solar energy.

“This study discovered a new way of using wood materials’ unique properties as both an excellent insulator and water vapor transporter,” said Z. Jason Ren, a professor in environmental engineering who recently moved from CU Boulder to Princeton, and the other co-leader of the team that performed the study.

The researchers treat the wood so that it loses its lignin, the part of the wood that makes it brown and rigid, and its hemicellulose, which weaves in and out between cellulose to hold it in place. The resulting “nanowood” is treated with silane, a compound used to make silicon for computer chips. The semiconducting nature of the compound maintains the wood’s natural nanostructures of cellulose, and clings less to water vapor molecules as they pass through. Silane is also used in solar cell manufacturing.

The membrane looks like a thin piece of wood, seemingly bleached white, that is suspended above a source of water vapor. As the water heats and passes into the gas phase, the molecules are small enough to fit through the tiny channels lining the walls of the leftover cell structure. Water collected on the other side is now free of large contaminants like salt.
To test it, the researchers distilled water through it and found that it performed 1.2 times better than a conventional membrane.

“The wood membrane has very high porosity, which promotes water vapor transport and prevents heat loss,” said first author Dianxun Hou, who was a student at CU Boulder.
Inventwood, a UMD spinoff company of Hu’s research group, is working on commercializing wood based nanotechnologies.

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

Hydrophobic nanostructured wood membrane for thermally efficient distillation by Dianxun Hou, Tian Li, Xi Chen, Shuaiming He, Jiaqi Dai, Sohrab A. Mofid, Deyin Hou, Arpita Iddya, David Jassby, Ronggui Yang, Liangbing Hu, and Zhiyong Jason Ren. Science Advances 02 Aug 2019: Vol. 5, no. 8, eaaw3203 DOI: 10.1126/sciadv.aaw3203

This paper appears to be open access.

In my brief survey of the paper, I noticed that the researchers were working with cellulose nanofibrils (CNF), a term which should be familiar for anyone following the nanocellulose story, such as it.

Preserving art canvases (think Van Gogh, Picasso, Vermeer, and others) with nanomaterials

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It has to be disconcerting to realize that your precious paintings are deteriorating day by day.  In a June 22, 2017 posting titled ‘Art masterpieces are turning into soap‘,

This piece of research has made a winding trek through the online science world. First it was featured in an April 20, 2017 American Chemical Society news release on EurekAlert,

A good art dealer can really clean up in today’s market, but not when some weird chemistry wreaks havoc on masterpieces [emphasis mine]. Art conservators started to notice microscopic pockmarks forming on the surfaces of treasured oil paintings that cause the images to look hazy. It turns out the marks are eruptions of paint caused, weirdly, by soap that forms via chemical reactions. Since you have no time to watch paint dry, we explain how paintings from Rembrandts to O’Keefes are threatened by their own compositions — and we don’t mean the imagery.

Here’s the video,


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Now, for the latest: canavases are deteriorating too. A May 23, 2018 news item on Nanowerk announces the latest research on the ‘canvas issue’ (Note: A link has been removed),

Paintings by Vincent van Gogh, Pablo Picasso and Johannes Vermeer have been delighting art lovers for years. But it turns out that these works of art might be their own worst enemy — the canvases they were painted on can deteriorate over time.

In an effort to combat this aging process, one group is reporting in ACS Applied Nano Materials (“Combined Nanocellulose/Nanosilica Approach for Multiscale Consolidation of Painting Canvases”) that nanomaterials can provide multiple layers of reinforcement.

A May 23, 2018 American Chemical Society (ACS) news release (also on EurekAlert), which originated the news item,  expands on the theme,

One of the most important parts of a painting is the canvas, which is usually made from cellulose-based fibers. Over time, the canvas ages, resulting in discoloration, wrinkles, tears and moisture retention, all greatly affecting the artwork. To combat aging, painting conservators currently place a layer of adhesive and a lining on the back of a painting, but this treatment is invasive and difficult to reverse. In previous work, Romain Bordes and colleagues from Chalmers University of Technology, Sweden, investigated nanocellulose as a new way to strengthen painting canvases on their surfaces. In addition, together with Krzysztof Kolman, they showed that silica nanoparticles can strengthen individual paper and cotton fibers. So, they next wanted to combine these two methods to see if they could further strengthen aging canvas.

The team combined polyelectrolyte-treated silica nanoparticles (SNP) with cellulose nanofibrils (CNF) for a one-step treatment. The researchers first treated canvases with acid and oxidizing conditions to simulate aging. When they applied the SNP-CNF treatment, the SNP penetrated and strengthened the individual fibers of the canvas, making it stiffer compared to untreated materials. The CNF strengthened the surface of the canvas and increased the canvas’s flexibility. The team notes that this treatment could be a good alternative to conventional methods.

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

Combined Nanocellulose/Nanosilica Approach for Multiscale Consolidation of Painting Canvases by Krzysztof Kolman, Oleksandr Nechyporchuk, Michael Persson, Krister Holmberg, and Romain Bordes. ACS Appl. Nano Mater., Article ASAP DOI: 10.1021/acsanm.8b00262 Publication Date (Web): April 26, 2018

Copyright © 2018 American Chemical Society

This image illustrating the researchers’ solution accompanies the article,

Courtesy: ACS

The European Union’s NanoRestART project was mentioned here before they’d put together this introductory video, which provides a good overview of the research,

For more details about the problems with contemporary and modern art, there’s my April 4, 2016 posting when the NanoRestART project was first mentioned here and there’s my Jan. 10, 2017 posting which details research into 3D-printed art and some of the questions raised by the use of 3D printing and other emerging technologies in the field of contemporary art.

Stronger than steel and spider silk: artificial, biodegradable, cellulose nanofibres

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This is an artificial and biodegradable are two adjectives you don’t usually see united by the conjunction, and. However, it is worth noting that the artificial material is initially derived from a natural material, cellulose. Here’s more from a May 16, 2018 news item on ScienceDaily,

At DESY’s [Deutsches Elektronen-Synchrotron] X-ray light source PETRA III, a team led by Swedish researchers has produced the strongest bio-material that has ever been made. The artifical, but bio-degradable cellulose fibres are stronger than steel and even than dragline spider silk, which is usually considered the strongest bio-based material. The team headed by Daniel Söderberg from the KTH Royal Institute of Technology in Stockholm reports the work in the journal ACS Nano of the American Chemical Society.

A May 16, 2018 DESY press release (also on EurekAlert), which originated the news item, provides more detail,

The ultrastrong material is made of cellulose nanofibres (CNF), the essential building blocks of wood and other plant life. Using a novel production method, the researchers have successfully transferred the unique mechanical properties of these nanofibres to a macroscopic, lightweight material that could be used as an eco-friendly alternative for plastic in airplanes, cars, furniture and other products. “Our new material even has potential for biomedicine since cellulose is not rejected by your body”, explains Söderberg.

The scientists started with commercially available cellulose nanofibres that are just 2 to 5 nanometres in diameter and up to 700 nanometres long. A nanometre (nm) is a millionth of a millimetre. The nanofibres were suspended in water and fed into a small channel, just one millimetre wide and milled in steel. Through two pairs of perpendicular inflows additional deionized water and water with a low pH-value entered the channel from the sides, squeezing the stream of nanofibres together and accelerating it.

This process, called hydrodynamic focussing, helped to align the nanofibres in the right direction as well as their self-organisation into a well-packed macroscopic thread. No glue or any other component is needed, the nanofibres assemble into a tight thread held together by supramolecular forces between the nanofibres, for example electrostatic and Van der Waals forces.

With the bright X-rays from PETRA III the scientists could follow and optimise the process. “The X-rays allow us to analyse the detailed structure of the thread as it forms as well as the material structure and hierarchical order in the super strong fibres,” explains co-author Stephan Roth from DESY, head of the Micro- and Nanofocus X-ray Scattering Beamline P03 where the threads were spun. “We made threads up to 15 micrometres thick and several metres in length.”

Measurements showed a tensile stiffness of 86 gigapascals (GPa) for the material and a tensile strength of 1.57 GPa. “The bio-based nanocellulose fibres fabricated here are 8 times stiffer and have strengths higher than natural dragline spider silk fibres,” says Söderberg. “If you are looking for a bio-based material, there is nothing quite like it. And it is also stronger than steel and any other metal or alloy as well as glass fibres and most other synthetic materials.” The artificial cellulose fibres can be woven into a fabric to create materials for various applications. The researchers estimate that the production costs of the new material can compete with those of strong synthetic fabrics. “The new material can in principle be used to create bio-degradable components,” adds Roth.

The study describes a new method that mimics nature’s ability to accumulate cellulose nanofibres into almost perfect macroscale arrangements, like in wood. It opens the way for developing nanofibre material that can be used for larger structures while retaining the nanofibres’ tensile strength and ability to withstand mechanical load. “We can now transform the super performance from the nanoscale to the macroscale,” Söderberg underlines. “This discovery is made possible by understanding and controlling the key fundamental parameters essential for perfect nanostructuring, such as particle size, interactions, alignment, diffusion, network formation and assembly.” The process can also be used to control nanoscale assembly of carbon tubes and other nano-sized fibres.

(There are some terminology and spelling issues, which are described at the end of this post.)

Let’s get back to a material that rivals spider silk and steel for strength (for some reason that reminded me of an old carnival game where you’d test your strength by swinging a mallet down on a ‘teeter-totter-like’ board and sending a metal piece up a post to make a bell ring). From a May 16, 2018 DESY press release (also on EurekAlert), which originated the news item,

The ultrastrong material is made of cellulose nanofibres (CNF), the essential building blocks of wood and other plant life. Using a novel production method, the researchers have successfully transferred the unique mechanical properties of these nanofibres to a macroscopic, lightweight material that could be used as an eco-friendly alternative for plastic in airplanes, cars, furniture and other products. “Our new material even has potential for biomedicine since cellulose is not rejected by your body”, explains Söderberg.

The scientists started with commercially available cellulose nanofibres that are just 2 to 5 nanometres in diameter and up to 700 nanometres long. A nanometre (nm) is a millionth of a millimetre. The nanofibres were suspended in water and fed into a small channel, just one millimetre wide and milled in steel. Through two pairs of perpendicular inflows additional deionized water and water with a low pH-value entered the channel from the sides, squeezing the stream of nanofibres together and accelerating it.

This process, called hydrodynamic focussing, helped to align the nanofibres in the right direction as well as their self-organisation into a well-packed macroscopic thread. No glue or any other component is needed, the nanofibres assemble into a tight thread held together by supramolecular forces between the nanofibres, for example electrostatic and Van der Waals forces.

With the bright X-rays from PETRA III the scientists could follow and optimise the process. “The X-rays allow us to analyse the detailed structure of the thread as it forms as well as the material structure and hierarchical order in the super strong fibres,” explains co-author Stephan Roth from DESY, head of the Micro- and Nanofocus X-ray Scattering Beamline P03 where the threads were spun. “We made threads up to 15 micrometres thick and several metres in length.”

Measurements showed a tensile stiffness of 86 gigapascals (GPa) for the material and a tensile strength of 1.57 GPa. “The bio-based nanocellulose fibres fabricated here are 8 times stiffer and have strengths higher than natural dragline spider silk fibres,” says Söderberg. “If you are looking for a bio-based material, there is nothing quite like it. And it is also stronger than steel and any other metal or alloy as well as glass fibres and most other synthetic materials.” The artificial cellulose fibres can be woven into a fabric to create materials for various applications. The researchers estimate that the production costs of the new material can compete with those of strong synthetic fabrics. “The new material can in principle be used to create bio-degradable components,” adds Roth.

The study describes a new method that mimics nature’s ability to accumulate cellulose nanofibres into almost perfect macroscale arrangements, like in wood. It opens the way for developing nanofibre material that can be used for larger structures while retaining the nanofibres’ tensile strength and ability to withstand mechanical load. “We can now transform the super performance from the nanoscale to the macroscale,” Söderberg underlines. “This discovery is made possible by understanding and controlling the key fundamental parameters essential for perfect nanostructuring, such as particle size, interactions, alignment, diffusion, network formation and assembly.” The process can also be used to control nanoscale assembly of carbon tubes and other nano-sized fibres.

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

Multiscale Control of Nanocellulose Assembly: Transferring Remarkable Nanoscale Fibril Mechanics to Macroscale Fibers by Nitesh Mittal, Farhan Ansari, Krishne Gowda V, Christophe Brouzet, Pan Chen, Per Tomas Larsson, Stephan V. Roth, Fredrik Lundell, Lars Wågberg, Nicholas A. Kotov, and L. Daniel Söderberg. ACS Nano, Article ASAP DOI: 10.1021/acsnano.8b01084 Publication Date (Web): May 9, 2018

Copyright © 2018 American Chemical Society

This paper is open access and accompanied by this image illustrating the work,

Courtesy: American Chemical Society and the researchers [Note: The bottom two images of cellulose nanofibres, which are constittuents of an artificial cellulose fibre, appear to be from a scanning tunneling microsscope. Credit: Nitesh Mittal, KTH Stockholm

This news has excited interest at General Electric (GE) (its Wikipedia entry), which has highlighted the work in a May 25, 2018 posting (The 5 Coolest Things On Earth This Week) by Tomas Kellner on the GE Reports blog.

Terminology and spelling

I’ll start with spelling since that’s the easier of the two. In some parts of the world it’s spelled ‘fibres’ and in other parts of the world it’s spelled ‘fibers’. When I write the text in my post, it tends to reflect the spelling used in the news/press releases. In other words, I swing in whichever direction the wind is blowing.

For diehards only

As i understand the terminology situation, nanocellulose and cellulose nanomaterials are interchangeable generic terms. Further, cellulose nanofibres (CNF) seems to be another generic term and it encompasses both cellulose nanocrystals (CNC) and cellulose nanofibrils (CNF). Yes, there appear to be two CNFs. Making matters more interesting is the fact that cellulose nanocrystals were originally christened nanocrystalline cellulose (NCC). For anyone who follows the science and technology scene, it becomes obvious that competing terminologies are the order of the day. Eventually the dust settles and naming conventions are resolved. More or less.

Ordinarily I would reference the Nanocellulose Wikipedia entry in my attempts to clarify the issues but it seems that the writers for the entry have not caught up to the current naming convention for cellulose nanocrystals, still referring to the material as nanocrystalline cellulose. This means, I can’t trust the rest of the entry, which has only one CNF (cellulose nanofibres).

I have paid more attention to the NCC/CNC situation and am not as familiar with the CNF situation. Using, NCC/CNC as an example of a terminology issue, I believe it was first developed in Canada and it was Canadian researchers who were pushing their NCC terminology while the international community pushed back with CNC.

In the end, NCC became a brand name, which was trademarked by CelluForce, a Canadian company in the CNC market. From the CelluForce Products page on Cellulose Nanocrystals,

…

CNC are not all made equal. The CNC produced by CelluForce is called CelluForce NCCTM and has specific properties and are especially easy to disperse. CelluForce NCCTM is the base material that CelluForce uses in all its products. This base material can be modified and tailored to suit the specific needs in various applications.

These, days CNC is almost universally used but NCC (not as a trademark) is a term still employed on occasion (and, oddly, the researchers are not necessarily Canadian).

Should anyone have better information about terminology issues, please feel free to comment.